Radio Electronics Magazine 09 September 1980

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:et up ahome video system ~olid-state sounder applications lew hi-Ii noise reduction system .

Build your own wipeout videogame Inside VHS recorder circuits New packaging system lor projects

A breadboard as 22 five-p oint terminals plus two 10-point bus strips. 0.3" ce nters; 1.9 x 2.1 x.4" (43 x 53 x 10mm).

46 five- point terminals plus two 20-point bus strips. 0.6" centers; 3.6 x 2.4 x .4" (91 x 61 x 10mm ).

EXPERIMENTOR 600 $12.05* 94 five-point terminal s plus two 40-p oint bus strips. 0.6" centers; 6.0 x 2.4 x .4" (152 x 61 x 10mm),

EXPERIMENTOR QUAD BUS STRIP $4.40* Four 40-point bus strips. 6.0 x 1.0 x .4" (152 x 25 x tornrn ).

EXPERIMENTOR 350 $6.05 * 46 five-point termin als plus two 20- point bus strips. 0.3" ce nters; 3.6 x 2.1 x.4 " (91 x 53 x 10mm).

EXPERIMENTOR 300 $10.95* 94 five-point terminals plus two 40- point bus strips. 0.3" ce nters; 6.0 x 2.1 x .4" (1 52 x 53 x 10mm).

Marked tie-points simplify translation from breadboards to PC boards or wiring tables .

Quick construction of microprocessors and other ci rcuits- each EXP-4B gives you four bus lines, with 8-, 12-,and 16-line address and data buses easi ly c reated by combining Bus Strips.


Instant hookup for all types of com pone nts, with push-in/pull- out ease. Adaptable for all types of co mponents . .. DIP-comp atible . . . confo rm to 0.1" grid ; jumpers are #22-30 solid hook up wi re. Mix and match large and sma ll chips in the same circuit. Use 300 -series socket s for sma ller DIPs; 600 -series with 0.6" center channel for full fan-out with larger chips. Infinite flexibility lets you expand and modi fy c ircuits vertica lly and horizontally, simp ly by snap ping sockets togethe r. Easy mounting using 4-40 screws from front or 6-32F self -tapping screws from rear. Vinyl-insu lated back ing - lets you fasten to any surface .

Ruggedly built of abrasion -resistan t materials that wit hsta nd 100°C.

It's hard to believe how much faster and easier building circuits can be . . . until you try our Experirnentor' solderless breadboarding sockets. From the largest DIPto the smallest resistor, components plug in and out instantly, without special hardware or jumper cables . So you save

time and money by eliminating soldering and component damage, Start small and expand in any direction your think ing takes you,by snapping sockets together vertica lly or horizontally. With no limit to your ideas. Get started today, for as little as $3.05 *!

Smarter tools for testing and design. 70 Fulton Terr. New Haven . CT 06509 (203) 624-3103 . TWX 710-465-1227 OTHER Off iCES: San francIsco (415) 421-8872. TWX 910-372-7992 Europe : Phone Saffron-Walden 0799-21682 . TLX 817477 Canada: Len f inkler Ltd.. Dcwnsview. Ontario


Call toll-free for details

1 800 243 6077 -



Du ring business hours

'S uggested u.s. resale. Prices. specifications subject to changewithout notice . CO Copyright 1980 Glo balSpecialties Corpo ration .



Bone Fane,.. A new concept in sound technology may revolutionize the way we listen to stereo music. The Bone Fone surrounds your entire body with a sound almost impossible to imagine. You're standing in an open field. Suddenly there's music from all directions. Your bones resonate as if you're listening to beautiful stereo music in front of a powerful home stereo system . But there 's no radio in sight and nobody else hears what you do. It's an unbelievable experience that will send chills through your body when you first hear it. AROUND YOU And nobody will know you're listening to a stereo. The entire sound system is actually draped around you like a scarf and can be hidden under a jacket or worn over clothes. The Bone Fone is actually an AM/FM stereo multiplex radio with its speakers located near your ears . When you tune in a stereo station, you get the same stereo separation you'd expect from earphones but without the bulk and inconvenience . And you also get something you won't expect. INNER EAR BONES The sound will also resonate through your bones-all the way to the sensitive bones of your inner ear. It's like feeling the vibrations of a powerful stereo system or sitting in the first row listening to a symphony orchestra-it's breathtaking. Now you can listen to beautiful stereo music everywhere-not just in your living room. Imagine walking your dog to beautiful stereo music or roller skating to a strong disco beat. You can ride a bicycle or motorcycle, jog and even do headstands - the Bone Fone stays on no matter what the activity. The Bone Fone stereo brings beautiful music and convenience to every indoor and outdoor activity without disturbing those around you and without anything covering your ear. SKI INVENTION The Bone Fone was invented by an engineer who liked to ski. Every time he took a long lift ride, he noticed other skiers carrying transistor radios and cassett e players and wondered if there was a better way to keep your hands free and listen to stereo music. 80 he invented the Bone Fone stereo. When he put it around his neck, he couldn't believe his ears. He was not only hearing the music

and stereo separation, but the sound was resonating through his bones giving him the sensation of standing in front of a powerful stereo system. AWARDED PATENT The inventor took his invention to a friend who also tried it on. His friend couldn't believe what he heard and at first thought someone was playing a trick on him. . T he inventor was awarded a patent for his idea and brought it to JS&A. We took the idea and our engineers produced a very sensitive yet powerfu l AM/FM multiplex radio called the Bone Fone. The entire battery-powered system is selfcontained and uses four integrated circuits and two ceramic filters for high station selectivity. The Bone Fone weighs only 15 ounces, so when worn over your shoulders, the weight is not even a factor. BUILT TO TAKE IT The Bone Fone was built to take abuse. The large 70 millimeter speakers are protected in flexible water and crush resistant cases. The case that houses the radio itself is made of rugged ABS plastic with a special reinforcement system. We knew that the Bone Fone stereo may take a great deal of abuse so we designed it with the quality needed to withstand the worst treatment. The Bone Fone stereo is covered with a sleeve made of Lycra Spandex-the same material used to make expensive swim suits, so it's easily washable . You simply remove the sleeve, dip it in soapy water, rinse and let the sleeve dry. It's just that easy. The entire system is also protected against damage from moisture and sweat making it ideal for jogging or bicycling . The sleeve comes in brilliant Bone Fone blue- a color designed especially for the system. An optional set of four sleeves in orange, red, green and black is also available for $10. You can design your own sleeve using the pattern supplied free with the optional kit. YOUR OWN SPACE Several people could be in a car, each tuned to his own program or bring the Bone Fone to a ball game for the play by play. Cyclists,

joggers, roller skaters, sports fans, golfers, housewives, executives-everybody can find a use for the Bone Fone. It's the perfect gift. Why not order one on our free trial program and let your entire family try it out? Use it outdoors, while you drive, at ball games or while you golf, jog or walk the dog. But most important-compare the Bone Fone with your expensive home stereo system. Only then will you fully appreciate the major breakthrough this product represents. GET ONE SOON To order your Bone Fone, simply send your check or money order for $69.95 plus $2.50 postage and handling to the address shown below . (Illinois residents add 6% sales tax.) Credit card buyers may call our toll-free number below. Add $10 if you wish to also receive the accessory pack of four additional sleeves . We'll send you the entire Bone Fone stereo complete with four AA cell batteries, instructions, and 90-day limited warranty including our prompt service-by-mail address. When you receive your unit, use it for two weeks. Take it with you to work, or wear it in you r car. Take walks with it, ride your bicycle or roller skate with it. Let your friends try it out. If after our two-week free trial, you do not feel that the Bone Fone is the incredible stereo exper ience we've described, return it for a prompt and courteous refund, including your $2.50 postage and handling. You can't lose and you'll be the first to discover the greatest new space-age audio product of the year. Discover the freedom, enjoyment, and quality of the first major breakthrough in portab le entertainment since the transistor radio . Order a Bone Fone stereo at no obligation , today.


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Dept. RE One JS&A Plaza Northbrook, III. 60062 (312) 564 -7000 Call TOLL-FREE . . . • • . . . 800 323-6400

In Illinois Call

(312) 564-7000 © JS&A Group, Inc.,1980





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The two wonders on this page are a· mong the best, most wanted, and most useful everyday electronic products in the world. Each one brings you state-of-the-art function and design and places awesome calculating power at your fingert ips. Let's examine these breakthroughs one at a time.



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ANATOMY OF YOUR FINGERTIP The Casio CoSO Chronographic Calculator is the first wrist inst ru me nt whose numeric and function command keys are designed so you can operate them with your fingertip . No need to carry a special stylus or look for a pencil with a sharp point whenever you want to calculate something. The Casio CoSO has an S-digit read-out. It adds, subtracts, multiplies, divides, and performs chain calculations. Floating decimal tool. It tells you the time digitally in two zones (accurate within ± 15 seconds a month). and it tells month and date. It's also a stopwatch in hundredths of seconds, with capacity up to 23 hrs., 59 min. 59.99 sees. It gives you both lap and net times as well. The CoSO weighs much less than metal calculator watches. The case and band are space-age unbreakable plastic, and the LCD face is protected by hard minerai glass. So far as we know, only one or two stores in New York City have been able to get the CoSO. And we've seen it advertised as high as $75.00 - and that only lets you reserve it, with a long wait for del ivery.


You can call our toll-free number for immediate delivery, and charge just $69.95 (plus $2.50 insured shipping) to your credit card . Thirty day moneyback guarantee, one-year parts and labor warranty. Just three more points: the battery's included . There's a tiny light to illumi nate the display at night. In fact, it 's bright enough to help you find your keys if you drop them in the dark. And when you receive your Casio C·SO, resist the temptation to press the keys with your fingernail. Not necessary . Just use your fingert ips. WORLDS SMALLEST PRINTING CALCULATOR! Besides all the calculating functions you expect, the Olivetti Logos 9 offers you these added features, plus more, thanks to some new technological breakthroughs. • Measure s only 1 inch by 2Y2 inches by 4 5/S inches, with full 12 digit liquid crystal display, with floating or fixed position decimal. • Exclusive paper cartridge system, simply slide up the calculator top and behold the smallest printing system you've ever seen . • Clear crisp entries on Olivett i's special cartridge paper. Each cartridge lasts for up to 1,300 entries. (Thirty two rolls ...good for three years of use, only $1S.00). • Incredibly fast printing speed of two lines per second, with print recall. Should your entries exceed unit speed, the Logos 9 will still print each entry. • Rechargable batteries (up to 500 reo charges per battery). • Printing head labels all numerical entries with letters. You'll never forget your entries purpose. . • Accumulating memory, plus fully independent memory. . • Digital clock, a totally accurate timepiece. • Ideal for people who employ, discounts, gross margins, and percentage markups. • Automatic average : The Logos 9 will automatically compute the average of a group of entries. • Complete memory recall and display. • Battery charging and 90 day limited warranty. • Easy Olivetti service by mail. CIRCLE 29 ON FREE INFORMATION CARD

Try this amazing pocket calculator today, we 're sure that you will agree that the Logos 9 is the most convenient and advanced pocket calculator you've ever seen . If after thirty days, you are not satisfied, return the unit for a prompt refund . The Olivetti Logos 9 was awarded at the International Consumer Electronic Show 19S0 the distingu ished position of being the "Most Innovative Product of the Year", and is the best selling pocket calculator in the world. Try it today. HERE'S HOW TO ORDER AND SAVE The CoSO Chronograph/Calculator is $69.95. The Printing Calculator is $S9. 95. That adds up to $159.90. If you order both for yourself (and don't forget gift possibilities) pay only $144.95 for a savings of $15.00. Or order any two and take $15.00 off their combined price. You can order today by calling one of our toll-free nurnbers for immediate delivery . You save on insured sh ipping charges, as well : just $2 .50 for each order, not each item . 30 DAY MONEY BACK GUARANTEE When you order, you're protected by our 30·day money back guarantee policy . And each item is additionally covered by a one-year parts and labor warranty. All units come with instructions, and batteries are included . Right now, call toll-free and charge what you want on American Express, Diners Club, Carte Blanche, Master Card, or Visa .

800·526·2801 800·257·7850 In New Jersey call toll free: 800-322-8650 N.J . residents please add 5% sales tax. You can also mail your order with check or money order to:

rii1 ffli:fcus=i ,! WJ 0


Dept. RE9, Lakewood Plaza Lakewood, New Jersey 08701




PLUG-IN MODULAR REMOTE CONTROL The BSR System X-10 p lugs into AC wall outlets to provide remote control operation of lamps and appliances in your home or office. Steven A. Clarcla

55 UNICORN-1 ROBOT PART 2. Assembling the man ipulator arms and " hands." James A. Gupton, Jr. 66




WIPEOUT VIDEOGAME Ten action-packed games in an arcade type videogame. Add on RF modulator and play it on your TV set. L. Steven Chealrs LOOKING AHEAD Tomorrow's news today. David Lachenbruch


SATELUTE TV NEWS The iatest happenings in an exciting new industry. Gary H. Arlen


PIEZOELECTRIC SOUNDER APPUCATIONS Sol id-state "beepers" have a variety of interesting circuit applications. This should give you a few ideas . calvin R. Grat, W5LFM


NEW IDEAS A winning circuit application from our readers .


Vol. 51 NO.9


You can turn on and off lamps and appliances without ever leaving your armchair with BSR's System X-10. To install the system, you simply plug the various modules into existing AC wall outlets. The system features a handheld ultrasonic remote control unit and a programmable timer. For a look at the circuitry and how the system works, turn to page 47.

78 HOBBY CORNER A one-arm bandit circu it plus a new packaging system for projects. Earl "Doc" savage, K4SDS


52 HOW TO HOOK UP HOME VIDEO SYSTEMS How to connect a programmable VCR, videogame, payTV , cable T.V.. and other inputs to a single TV set . Frank Gates 70


VHS TRANSPORT CIRCUITS A look at the circuitry that controls the transport mechanism in VHS videotape recorders and how to troubleshoot it. Forest Belt


SERVICE CUNIC Typical problems with tripler circuits and some not so typical. Jack Darr


SERVICE QUESTIONS R-E's Service Editor solves techn icians ' problems.

61 NEW NOISE REDUCTION SYSTEM The new High-Com II system from Nakamichi prov ides 18-dB more noise reduction in tape recorders than Dolby B. Len Feldman

63 R.EAL. SOUND LAB TESTS B.I.C.lAVNET MODEL T-3 CASSETTE DECK Medium-priced cassette deck rates superb. Len Feldman




NEW NOISE REDUCTION SYSTEM for tape recorders provides 18-dB more noise reduction than Dolby B. For the complete details, tum to page 61.


38 40 42 43 122 16 103 102 16 123

COMMUNICATIONS CORNER Transceivers with all the operating controls built into the m icrophone. Herb Friedman The DefenderT5-1 CB Antenna Tuner/Monitor lET Model RC5-500 RoCSubstitution Box Datong Model AD-170 Active Antenna Micronta BP-1 Blood Pressure Tester Advertising Index Advertising Sales Offices Books Computer Reports Editorial Free Information Card

26 105 103 83 94 100 7

Letters Market Center New Lit New Products Radio Products Stereo Products What's News

HANDS FOR THE UNICORN-1 ROBOT are solenoid activated. For details on how to assemble the manipulator arms and hands, tum to page 55.

Radio-Electronics, (ISSN 0033-7862) Published monthly by Gernsback Publications, Inc., 200 Park Avenue South , New York , NY 10003. Phone: 212-777-6400. Controlled Circulation Postage Paid at Concord , NH. One-year subscription rate : U.S.A. and U.S. possessions, $13.00. Canada, $16.00. Other countries, $18.00. Single copies $1.25. © 1980 by Gernsback Publications, Inc. All rights reserved . Printed in U.S.A. Subscription Service: Mail all subscription orders, changes. correspondence and Postmaster Notices of undelivered copies (Form 3579) to Radio-Electronics Subscription Service, Bo x 2520, Boulder, CO 80322. A stamped self-addressed envelope must accompany all submitted manuscripts and/or artwork or photographs if their return is desired shouid they be rejected . We disclaim any responsibility for the loss or damage of manuscripts and /or artwork or photographs whil e in our possession o r otherwise.






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As s service to readers, Radio-Elaetronlcs pUblishes availabla plans or Information relating to newsworthy products, tachnlques and scientific and tachnologlcal developments. Because of possible variances In the quality and condition of materials and workmanship used by readers, Radlo-Elactronlcs disclaims any responsibility for the sate and proper functioning of reader-buiil projects based upon or from plans or Infonnatlon publfshad In this magazine.





A 3-disc race : General Elect ric th rew the already complex videodisc race into pandemonium by embracing a third system -VHO (Video High Density ), developed by the Japan Victor Company (JVC). The VHD system uses a 10inch grooveless disc to play two hou rs (one hour per side) of color and stereo-sound information by reading out capacitance variations in the disc material. The disc revolves at 900 rpm , and has features in common wit h bot h other consumer systems. Like the RCA CEO (Capacitance Electronic Disc) system, the stylus and disc form the plates of what, in effect, is a variable capacitor; but the RCA system uses grooves to guide the stylus , wh ile VHD employs pilot frequencies that differ between adjacent t racks. Like the Philips-MCA optical system , it's groo veless and is capable of certain special effects, such as fast, slow , and reverse motion. The CEO disc revolves at 450 rpm and plays one hour per side. The optical di sc spins at 1,800 rpm (30 minutes per side) in the special-eff ects mode and at a speed varying from 600 to 1,800 in the so-ca lled " co nstant linear velocity mode " (60 minu tes per side). The three systems are totally-and hopele ssly-incompatible with each other. GE's espousal of the VHD system came in talks (nearing completion at press time) to establish thre e jointly owned companies : 1. With Matsushita (Panasoni c and Quasar) and JVC to manufacture players in the United States. 2. With those compan ies and Thorn EMI of England to press discs here. 3. With the same three comp anies to acquire rights and develop disc programm ing. VHD starts up far behind its competitors as a true dar k horse. Players for the optical system are already being marketed by Magnavox and Pioneer; disc s are being sold by MCA DiscoVision. RCA plans a nationwide laun ch fo r the SelectaVision CEO system early in 1981; Zenith wi ll also sell CED players and both RCA and CBS will press dis cs. JVC says that the VHO system can be on the American market by the end of 1981 at a price " compet it ive" to RCA's $500 target (the Magnavox and Pioneer players are $775 and $749, respectively). Who's on first? RCA was the best-sell ing color-TV brand in the 1980 mo del-year (July 1979-June 1980), accord ing to a survey by the industry newslette r Television Digest. That was th e second cons ecut ive model-year in which RCA was in the NO. 1 spot , getting a 21% share of the market to Zenith 's 20.5%. GE, with 7.5%, was NO.3 in color, followed by Sears Roebuck, also with 7.5% (but slightly lower in averag e ranking), Mag navox and Sony , with 7% and 6% respective ly. In black-and-white, Zenith easily retained t he top spot, registering 16% of the market , w ith RCA second at 14.85%, GE third with 10%, followed by Sears (9%) and Panasonic (6.65%). (J)



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More new VCR's: Videocassette recorders continue to spo rt a pro fus ion of new features . Both VHS and Beta mod els under major t rade names now include hig h-speed scan in both directions for easy program-segment selection (and for zipping th roug h commercials) as well as no ise-free still-frame, frame-by-fram e advance and slow motion , all controlled by a wired remot e unit. Akai has introduced t he first model w ith dual soundtracks-a two -

speed VHS portab le capable of carrying stereo audio or tracks in different languages. It also is the f irst mode l to be marketed in the United States that includes Dolby noise reduction. JVC has introduced what (at least for the moment) is the lightest and sma llest portable VCR available in the United States. It weig hs 11.4 po unds and can be backpacked and operated by a hand-held remote cont rol. Meanwhile, the two longitud inal video recorders scheduled for int rod uction in t he home market have been scratched. BASF's unit, which already was in the early stages of pilot production in a California plant, was officially withdrawn and the plant put up for sale. The Toshiba LVR wi ll probably appear first as a data recorder, it may eventually surface aga in in its video fo rm. At last June's Consumer Electron ics Show, Toshiba showed a new version of the LVR that can record two programs simultaneously by usin g two tracks, but the official word is that unti l further notice, LVR is no long er a co nsumer prod uct. Telecaptio ns : The expert s may argue long and loud over w hat fo rmat for teletext and viewdata should be adopted in the United States, but one form of vertica l-interval message transm ission is off and running and an unqualified success. Thi s is Telecaptioning, a special service for the hard of hearing, now permitted by the FCC. Captions are prepared by the Natio nal Captioning Institute for programs submitted by ABC, NBC, and PBS. CBS chose not to participate , arguing that teletext is better suited for captio ning . Sears Roebuc k has the exc lusive rights to sell decoders whi ch enab le TV sets to display the capti ons, as we ll as dec od er-equi pped TV sets, using IC's made by Texas Instru ments. In t he first 11 weeks of caption ing, Sears sold 17,700 capt io n decod ers, an average of 1,600 per week, but at the end of t he period (June 1), sales were running at the rate of 1,800 week ly-matching the current prod uction rate-with a fo ur-week orde r backlog . The decoders retail for $250, and a newly introduced 19-inch set wit h bui ltin decoder (in Sears ' fall catalog) lists for $520. The decoders have a thre e-position selector switch, and captioni ng eventually will be offered in Spanish as well as English, alo ng with " Infodata," a new information service being developed by Natio nal Captioning Institute. The Institute is supported by royalties from the sale of decoders. End of an era : The g rand old name in automobile radioMotoro la-has discontinued manufacture of car sound equipment for the general public. The company sold its car radio business to Texstar, which will use the Motorola name in the U.S. and Canada. Motorola also sold its Italian subs idiary Autovox, which makes TV sets, audio and car radio equipment, to a Swiss company, ending its direct involvement in consumer electronics. Its former TV-radio operation is now Quasar Electronics, a subsidiary of Matsushita. Motorola will continue to manufacture automotive electronic equipment, including radios , for sale to car manufacturers. DAVID LACHENBRUCH CONTRIBUTING EDITOR

Facts from Fluke on low-cost DMM's

Is this any ~ay to treat a $139IDultilDeter? In the rough world of industri al electronics, even a precision test inst ru ment ca n get treated like dirt. You need all t he ruggedn ess and depe ndab ility you can get in a DMM for field use. You'll find t hese qu aliti es and more in the Flu ke line of low-cost DMM's. Our D MM's have been dropped from t owers, ste pped on, and run over by const ruc tion equipment. And t hey've su rvived becau se we never cut corners on quality, even on our lowest -priced, six-function Model 8022A Troubleshooter at $139 U.S. Take a close look at a low-cost DMM from Fluke and you'll notice tough, lightweight construction that stands up t o the hard kn ocks of life.

Sturdy internal design and high-impa ct, flame-ret ardant shells make th ese units pra ctically indestructible. Right off the shelf, they meet or exceed severe military shock /vibration tests. Even our LCD's are protected by cast-tempered plastic shields. We use rugged CMOS LSI circuitry for integrity and endurance, and devote a large number of

components to protection against overloading, accidental inputs and operator err ors. We go to these lengths with all our low-cost DMM's to make sure they are genuine price/performanc e values. You can count on that. Becau se, that's what leadership is all about. For more facts on DMM reliability and where to find it, call to ll free 800-426-0361; use the coupon below; or contact your Fluke sto cking distributor, sales office or representative.

B022A Multimeter

I I : I I

IN THE U.s. AND NONEUROPEAN COUNTRIES: John Fluke Mfg. Co.•Inc. P.O. Box 43210 MS #2B Mountlak e Terrace, WA 98043

IN EUROPE: Fluke (Holland) B.V. P.O. Box 5053.5004 EB Tilburg, The Netherlands

(200) 774-2481

(013) 673 973

: Telex: 152662

Telex: 52237


o Please send B022A specificati ons. o low-cost Please send all t he facts on Fluk e DMM's. 0

Please have a salesma n ca ll.

Mail St op

Sta te

Zip Ext.

For literature circle no. 53

RE9/ 80


lhe neW modular drcult bu\\dlng sVstem deSlgned espeda\\v for electronlC hobbVlStS,

vvhaf:s rlevvs Weathe r " color" radar 10 get distance con trol A new technique that enhances the valu e of airborne weather radar has been announced by RCA. In 1977 that company p ionee re d airborne color r adar , which gives an airplane pil ot inf orma tio n not only of the presence and positi on of a storm, but of the strength of the precipitation. The colors vary from gree n, for lightest rainfall, to red, the most int ense . Present radars give exce llent information to the pilo t trying to fly aro und a sto rm. But they can -and often do-underestimate the intensity of precipitation in its remoter areas . Th at is because signals from those areas are attenuated by the heavy rain in t he neare r part s. Thu s, if a radar disp lay shows a yellow area behind a red one, it can mean either that the rain is lighter behind the intense storm or that the rain in the red area has so weakened the signal t hat int ense precip itatio n behind the red area is be ing unde rstated as yellow . REACT (Rain Echo Attenuation Compensation Technique) acts as a sort of automat ic gain control that compensates for atte nuat ion by water drops in the closer parts of the storm by increasi ng the gain of the radar receiver for the more distant areas by an amount equal to the two -way attenuation thr ough the nearer ones. If the retu rn signal is too weak to be seen even with REACT, the radar displays a blue, or " blind" area, w hich tells the pilot that the inte nsity of the storm in that area is unknown -it cannot be seen by the radar.

50-inch flat TV "tube" to arrive before 19901 The concept of a 30 X 40-inch (50-inch diagonal) flat TV display was described by

RCA scientists to the Society of Informat ion Displa y at their recent conference in San Diego, CA. The new picture-on -thewall "tube" will have decid ed advantages in brightness and picture quality over pres ent projection equipment of similar size and will require far less space. The display would consist of 40 modu les, each 1 inch wide and 30 inches high . (Exper imental displays of up to five modules have been con structed, but no complete unit has yet been made .) As in earlier concepts of a flat TV tube (Radio -Electronics, March 1957, page 43) the electron gun pro jects its beam paral lel to the phosphor screen . To turn the beam (and control vertical scann ing) one of a series of hor izontal wires-normally held between 250 and 350 volts pos itive-is switched negat ive (50 to 100 volts) . That repels the beam , "extracting" it and sending it at a right angl e through mesh-like beam guides-maintai ned at 40-80 volts pos iti ve-to the phosphor screen, held at about 1300 volts. Vanes on each module scan the beam hori zontally across the screen . Program modulation is applied through a series of vertical wires or electrodes. As to when the new tube (or disp lay) will be perfected, an RCA spokesman says: "While we are optimistic, we are by no means certain as to when all the problems fac ing us will be overcome. It will probably be close to 1990 before such a flat panel display can be manufactured at a pr ice the home consumer will be willing to pay. "

cent , memory and the rest. But in addition, it is programmed to give you the day of the week in which any date falls-80 years in the past and 120 years in the future. That should be particularly useful to production planners who have to know on what days week -ends and holidays fall, sometimes farther in advance than availab le calend ars show.

Pocket calculator includes twohundred-year calendar.

The little calculator also provides a digital clock service and a 24-hour alarm that can be preset fo r two ti mes in one day or be prep rogrammed up to a month in advan ce. As a special feature, the Time Capsule can also show the entire calendar, a mon th at a time, with the present day flashing. The calculator measures 4.9 X 2.7 X 0.3 inches . Suggested retail price is $59.95.

The Toshiba Time Capsule liqu id crystal calculator, just announced , includes the stand ard fou r func tions , square root, per-


THE TOSHIBA LC -840WA CALCULATOR can show, at one time, t he calendar for the month, with present date flashing, the lime down to the second, and the time for which the alarm has been set.

Magnavox will make no claims on AM stereo broadcasters






THE FLAT- PANEL TV DISPLAY would consist of 40 modules, eac h with its own el ectron gun, beam guides, and modulati on e lectrodes, fastened side-by-side to form a 40-inch-wide and 30- inch-high display. RCA sc ien t ists hope that the new " t ub e" will reach the market some time before 1990.

Magnavox Consumer Electronics Co. will not assert its AM Stereo broadcast patents against broadcasters or broadcast equipment manufacturers, says Magna vox president Meinken. However, " a reasona ble license fee will be charged to receiver manufacturers." The Magnavox AM Stereo system was approved by the FCC early last April. The company points out that among the advantages of the system are its pilot tone , which can be used to switch the receiver from mono to stereo automatically, at the same time turn ing on a light that tells the listener the program is in stereo . The pilot ton e can also carry a th ird channel of alphanum eric data, such as call lett ers or a weather alert.

continued on page 13






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NRI will train you at home to be an electronics professional in the growing world ofcommunications. Learn to service, repair, and install everything from microwave antennas to two-way radios ... from radar sets to TV transmitters.

TVThpe Recorders

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No other home-study course gives you such complete, professional training inso many fields ofcommunication. No other gives you the actual bench training with kits and demonstration units specially designed for learning. Only NRI gives you the thorough preparation and training you need to achieve professional competence in the wide world of communications.

Learn at Home in Your Spare Time Learn atyour own pace, right in your own home. There's no need to quit your job ortie up your evenings

with night classes. No time orgas wasted traveling to school...NRI brings it all to you. You learn with NRI-pioneered "bite-size" lessons and proven, practical "power-on" training.

meter and digital CMOS frequency counter. NRI even gives you special lessons to get your Amateur License so


BOOd Your Own 2-Meter, Digitally Synthesized VHF 'Iransceiver or 40-Channel CB NRI training is "hands-on" training. You get honest bench experience as you build and test this industrial-quality two-way radio and power supply. You reinforce theory lessons as you induce and correct faults, study individual circuits and learn how they interface with others. Or, at your option, you cantrain with a full forty-channel mobile CB and basestation power supply converter. You also build and keep for use inyour work atransistorized volt-ohm

you can go onthe air with your VHF transceiver.

FCC License or Full Refund

In all, you get 48 lessons, 9 special reference texts, and 10 training kits ...the training you need to become • ,.. aprofessional. And NRI includes train- ing for the required FCC radiotelephone license examination. You pass oryour tuition will be refunded in full. This money-back agreement is valid for six months after the completion ofyour course.

Free Catalog, No Salesman Will Call MoblleRadio

NRI's free, 100-page full-color catalog shows all the equipment you get, describes each lesson and kit in detail, tells more about the many specialized fields we train you for. It includes all facts onother interesting areas like TV and audio servicing or digital computer electronics. Mailthe postage-paid card and see how we can make you a pro. If the card has been removed, write to:

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VIIhat-s "eVlls continued from page 7

TV sales off in early 1980home VTR sales on the rise Sales of color television sets to retailers in the first 17 weeks of 1980 were 2,811,307, reports the Electric Industries Association . That is a decline of 5.7 percent from the 2,980,951 sets sold during the same period in 1979. Black-and-wh ite sales in the same period were 1,593,733, a decrease of 12.4 percent from the 1,818,667 units sold in the first 17 weeks of last year. Home video-tape recorder sales to retailers jumped 57.1 percent over last year189,550 units as against 120,674 sold in the first 17 weeks of 1979.

New energy-saving light bulb North American Philips Lighting Corporation has developed a new type of light bulb that, when compared with the conventional incandescent lamp, will last 7% times longer and use 70% less energy. The new lamp is an 11-watt, low-pressure mercury lamp of the fluorescent type, and is similar in size and shape to conventional bulbs; it is designed to fit standard light sockets. Low-pressure sodium lamps first appeared in Europe , during the 1930's and were about as efficient as mercury vapor lamps, which produced 40 lumens per watt. The new lamps achieve a fourfold increase in efficiency by integrating the development of rare earth fluorescent powders and radical miniaturization. The light in the new bulbs Is generated by converting ultraviolet radiation to visible light by means of using fluorescent powder on the inner surface of the bulb wall. The new rare earth powders also opened up the possibility of combining good color-rendering qualities with high efficiency. The new lamp is expected to replace standard light bulbs for both indoor and outdoor use in private homes, apartments, garages, commercial buildings, and stores. It has low glare, provides excellent contrast, and is not affected by changes in the surrounding temperature. It will be available in 240- and 120-volt versions. 120 volts is the predominant range in the United States and it will be available in the U.S. market early in 1981. A comparison between the cost , length of life, and performance of a standard 60watt soft-white incandescent lamp and one of the new SL-18 lamps shows the following: The incandescent lamp has a life expectancy of 1000 hours , while the new lamp has a life expectancy of 7500 hrs. The new lamp costs $12.00 . To obtain the equivalent life span, 7% incandescent lamps are required at a cost of $.85 each, for a total cost of $6 .37. During the 7500hour life span, the inca ndescents will consume 450 kilowatt-hours while the SL-18 consumes 135 kilowatt-hours. The savings

THE NEW SL-18 is close in size to the standard 6O-walt incandescant lamp, and is designed to fit standard light sockets. It will last 7'1. times longer than the oldstyle bulb and consume 70% less energy, reflecting a substantial decrease in the user's electric bills.

in the user's electric bill depend upon the unit cost per kilowatt-hour; at 2¢ per kilowatt-hour, the incandescents cost $9.00, the SL-18 $2.70 ($6.30 saved). At 4¢ per kilowatt-hour, the incandescents cost $13.50, the SL-18 $4.05 ($9.45 saved). At 6¢ per kilowatt-hour, the incandescents cost $27.00, the SL -18 $8.10 ($18 .90 saved); and the savings increase where the unit price for energy is higher. Worldwide, the lamps will immediately be available in four wattages: 11 watts, 13 watts, 18 watts, and 25 watts, as direct replacements for the standard 40-watt, 60watt, 75-watt, and 100-watt incandescent lamps most widely used today. There can be no doubt that the reduced energy consumption, reflected in lower electric bills, and the longer life of the new bulb will more than offset the higher initial price.

Technologies of the '80's may alter our lifestyles Westinghouse scientist George F. Mechlin described-at a Pittsburgh press briefing on "Technologies of the '80's: Myths, Facts, and Promises" -seven technologies that will have a significant impact on American society in the next decade. At the same time, he warned against the "myth" that anyone of them-or all of them combined-can present a "quick fix" for our present difficulties. The seven technologies are: Lasers, already handling fantastic tasks, and beginning to be used to harden metals, read video discs, and separate uranium. Optics, now able to transmit a million telephone calls for only .00 1 watt of laser light, and which will make information-processing a billion times faster than is remotely

possible with present technology. Microprocessors, which will invade every field of industry, transform office procedures, and have a bigger impact on our home life than the changes brought about by TV. Robotics, to do the dangerous, heavy, hot, and monotonous jobs now handled by human beings. Solar power, use of which will increase as and when it becomes economical. Coal conversion, into gas, oil, gasoline or methanol, generating power without the present pollution. Fuel cells, which will be developed into compact, efficient, and non-polluting energy sources. But, Dr. Mechlin warned, the very promise of technology has led to several overoptimistic myths that will lead to disillusionment. Most dangerous of those is the Myth of the Quick FiX, which leads many to hope for a near-immediate solution of many present diff iculties-particularly of the energy problem. "An alarm ing mistake," stated Dr. Mechlin, firmly. "No technical innovation has ever taken hold immediately. Even if a new energy source were discovered tomorrow, it would be unlikely to go 'on line' until the next century,"

World's longest single-span fiberoptic video link The longest single-span fiber-optic video service in use today was completed last April by Times Fiber Communications and is part of Vision Cable's system serving 20,000 cable-TV subscribers in 13 New Jersey communities. The new 2.4-kilometer link, that was completed in only six days, uses no repeaters and carries five channels per-fiber with studio-transmission quality, demonstrating the practicality of Fiber-optic communications. It consists of three-conductor optical cable and electro-optical equipment manufactured by Times. One fiber-conductor serves as a final leg for televised sports events presented at Madison Square Garden and Nassau Coliseum. The fiber carries the signals from microwave receivers at the headend to the studio for signal-processing and programming. A second fiber returns the program material, along with satellite signals and other studio-originated channels, to the headend for distribution to the subscribers. A third fiber will be used for future programming. The system is Frequency-modulated and exceeded contract performance specifications, with a measured 53-58 dB signal-tonoise level and no visible degradation of the picture. Vision Cable supplies 130,000 subscribers In the east and north, and additional fiber-optic links are planned for the future.


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PUBLISHER'S LETTER Home-Study Schools Cancelled GI Bill Not Funded Th at could be a minor headline in your local newspaper in the nottoo-distant future. Actions now taking place in Congress cou ld make that headline happen. Radio-Electronics carries a good deal of Home-Study school advertising . It is important to our readers. So when an act ion occurs that may reduce its availability to many of our readers, we feel it is important enough to tell you the facts. Here's the story. On June 3, 1980, the Veterans Affairs Committee reported to the budget committee of the House of Representatives and recommended that home-study and flight school instructions no longer be funded through the Veterans Administration . If that recommendation is passed by Congress, Veterans will no longer receive this important benefit. . Why are we so concerned? After all the veteran could still attend a resident school and have his education paid for. There are severa l practical problems with this answer. 1. There may be no resident school in the city whe re the veteran lives. 2. Even if there is a resident school in the city where he lives, it may not be convenient for him to reach it after work. 3. Some resident schools do not offer the best possible tra ining, and if a veteran can only attend a resident school , his freedom of choice is severely limited. 4. Correspondence schools permit the student to learn at his own pace and fit his education into his own schedule. Tho usands of veterans have taken home-study school courses and made those courses an important part of their career training. Personally, I got started in electronics by taking a DeForest Technical Training course while I was in the US Army . I fin ished it after being discharged. 5. Home-Study schools are much less expensive than the equivalent resident school. Resident schools can cost from two to five times as .much- so eliminating home-study can actually increase the cost of providing benefits. Radio-Electronics has a vested interest in not losing the advertising dollars we earn each year from correspondence school advertising. But we have an even greater interest in the future of our country and the careers of its veterans. If you agree with our viewpoint, it is urgent that you contact your Congressmen immediately. Let them know that you do not want them to take this extremely important benefit away. Write a letter, a mailgram, or send a telegram right now. Tomorrow could be too late.


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Cover design by Lo uis G. Rubsa men Cover photo by Robert Lewis

Radio Electronics is indexed in Applied Sc ience & Technology Index and Readers Gu ide to Periodical Literature.

Ge rnsback Pub lications. Inc . 200 Park Ave. S.. New York , NY 10003 (212) 777-6400 Pres ident : M. Harvey Gerns back Vice Preside nt : Larry Steck ler Sec retary/Treasurer : Caro l A. Gernsback

ADVERTISING SALES Larry Steckler Pub lisher EAST Stanley Levitan Radio-E lectronics 200 Park Ave. Sout h New Yo rk , NY 10003 (212) 777-6400 MIDWEST/Texas/Arkansas/Okla. Ralph Bergen The Ralph Bergen Co. 540 Frontage Road-S uite 361-A Northfie ld, Ill inois 60093 (312) 446-1444 PACIFIC COAST Mountain States Jay Eisenberg J.E. Publishers Representat ive Co., 8732 Sunset Blvd .. 4t h Floor, Los Angeles, CA 90069 (213) 659-3810 San Francisco, CA 94124 (415) 864-3252 SOUTHEAST Pau l McGi nn is Pau l McGinnis Company 60 East 42nd Street New York , N.Y. 10017 (212) 490-1021

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Hugo Gernsback (1884-1967) founder M. Harvey Gernsback, editor-in-chief Larry Steckler, CET, pub lisher Arthur Kielman, managing editor Josef Bernard, K2HUF, tec hnical ed itor Jack Darr, CET service editor Leonard Feldman contributing high -fidelity editor Karl Savon, semiconductor editor Herb Freidman, communications editor David Lachenbruch, contributing editor Earl "Doc" Savage, K4SDS, hobby ed itor Ruby Yee, production manager Robert A. W. Lowndes, production associate Marie J. Stolfi, production assistant Gabriele Margules, circulation director Arline R. Fishman, advertising coordinator


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Sabtronics gives you DMM and Frequency Counter kits with more features, better performance and incredibly low er prices Model2010A Bench/Portable DMM: $79.95 kit Features: 3 Yz digit LED display. 31 measurement ranges 6-Functions · 0.1% Basic DCV accuracy . 'Iouch-and-hold capability • Hi-Lo Ohms • 40 Hz to 40 kHz frequency response. Aut o Zero, Aut o Polarity • Ov erload protected • Overrange indication • Single chip LSI logic. Laser-trimmer reo sistor network and ul t ra-st able band-gap reference for better long term accuracy . Builr-ir. NiCd b attery charging circuit. Brief Specifications: OC \bIts 100llV to 1000V in 5 ranges; AC Volts 100llV to 1000V in 5 ranges; DC Current 0.11lA to lOA in 6 ranges; AC Current O.11lA to lOA in 6 ranges;Resistance O.W to 20MQ in 6 ranges; Diode Test Current 0.11lA to 1mA in 3 ranges; Input impedance, 10MQ on AC and DC vo lts; Power requirement, 4.5 to 6.5 VDC (4 "C" cells) o r o ptional AC adapte r/ charger.

Model2015A Bench/Portable DMM: $89.95 kit Same features and specifications as Model2010A except with large, 0.5" LCD Wz digit display. Optional Accessories: # AC-115, AC adapter/charger $7.9 5 #THP-20, Touch and Hold Probe $19.95 #NB-120 NiCd Batt ery Set $18.75

Model 8610A Frequency Counter: $99.95 kit Features: 8-digit LED display. 10Hz to 600 MHz guaranteed frequency range (5 Hz to 750 MHz typical) • 3 Gate times • 10 MHz T C XO Time base » Auto decimal point . Ove rflow indicator. Leading zero blanking • Resolution to 0.1 Hz • Built-in charging circuit for NiCd batteries. Brief Specifications: Freouency Range, switch selectable, 10 MHz, 100MHz, 600 MHz· Sensitivity, ± lOmV RMS to 100 MHz, ±50mV RMS, 100 MHz to 450 MHz; 90mV RMS 450 MHz to 600 MHz • Impedance, 1 MQ, 10 MHz and 100 MHz ranges; 50Q, 600 MHz range • Gate time (switch selectable) 0.1 sec, I sec, 10 sec • Temperature stability, 0.1 ppm/oC • Ageing rate < ± 5 ppm/ yr. Accuracy, I ppm or 0.0001% • Input protection , 150V RMS to 10 kHz (declining with frequency). Power Requirement, 4.5 to 6.5V OC @ 300mA (4 "e" cells) or op tional AC adapter! charger (7.5 to 9V DC @ 300mA). Ordering information USA- Add $6.00 per kit for shipp ing & handling. Personal checks have to clear before goods are shipped (allow 2-3 weeks). For faster delivery send cashiers check or money order. 10% dep osit for C.O. D. orde rs. Florida residents add sales tax. OVERSE AS-Add $25.00 per kit for airmail deli very. Payment by bank draft in U.S. funds.

Also available Model 811 OA, same as 8610A except maximum frequency is 100MHz and without battery charging circuit: $69.95 kit


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In Canada contact: Kumar & Co. Mississauga, Ont . Canada L5L 1H2

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Learning electronics •IS no pICDlC. ••


At any level it takes work and a few sacri&ces. But with eIE, it's worth it.

Whoever said, "The best things in life are free;' was writing a song, not living a life. Life is not just a bowl of cherries, and we all know it. You fight for what you get. You get what you fight for. If you want a thorough, practical, working knowledge of electronics, come to CIE. You can learn electronics at home by spending just 12 hard-working hours a week, two hours a day. Or, would you rather go bowling? Your success is up to you. At CIE, you earn your diploma. It is not handed to you simply for putting in hours. But the hours you do put in will be on your schedule, not ours. You don't have to go ~o a classroom. The classroom comes to you.

Why electronics training? Today the world depends on technology. And the "brain" of technology is electronics. Every year, companies the world over are finding new ways to apply the wonders of electronics to control and program manufacturing, processing ... even to create new leisure-time products and services. And the more electronics applications there are, the greater the need will be for trained technicians to keep sophisticated equipment finely tuned and operating efficiently. That means career opportunities in the eighties and beyond. Which CIE training fits you? Beginner? Intermediate? Advanced? CIE home study courses are designed for ambitious people at all entry levels. People who may have: 1. No previous electronics knowledge, but do have an interest in it; 2. Some basic knowledge or experience in electronics; 3. In-depth working experience or prior training in electronics. You can start where you fit and fit where you start, then go on from there to your Diploma, FCC License and career. Many people can be taught electronics. There is no mystery to learning electronics. At CIE you simply start with what you know and build on it to develop the knowledge and techniques that make you a specialist. Thousands of CIE graduates have learned to master the simple principles of electronics and operate or maintain even the most sophisticated electronics equipment. CIE specializes exclusively in electronics. Why CIE? CIE is the largest independent home study school that specializes exclusively in electronics. Nothing else. CIE has the electronics course that's right for you. Learning electronics is a lot more than memorizing a laundry list of

facts about circuits and transistors . Electronics is interesting! It is based on recent developments in the industry. It's built on ideas. So, look for a program that starts with ideas and builds on them . Look to CIE. Programmed learning. That's exactly what happens with CIE's Auto-Programmed" Lessons. Each lesson uses famous "programmed learning" methods to teach you important principles. You explore them, master them completely, before you start to apply them . You thoroughly understand each step before you go on to the next. You learn at your own pace. And, beyond theory, some courses come fully equipped with electronics gear (the things you see in technical magazines) to actually let you perform hundreds of checking, testing, and analyzing projects .

Experienced specialists work closely with you. Even though you study at home, you are not alone! Each time you return a completed lesson, you can be sure it will be reviewed, graded and returned with appropriate instructional help. When you need additional individual help, you get it fast and in writing from the faculty technical specialist best qua lified to

answer your question in terms you can understand. CIE prepares you for your FCC License. For some jobs in electronics, you must have a Federal Communications Commission (FCC) License. For others, some employers tend to consider your license a mark in your favor. Either way, your license is government -certified proof of your knowledge and skills. It sets you apart from the crowd. More than half of CIE's courses prepare you to pass the governmentadministered exam. In cont inuing surveys, nearly 4 out of 5 graduates who take the exam get their licenses! You can be among the winners. Today is the day. Send now. Fill in and return the postage-free card attached. If some other ambitious person has removed it, cut out and mail the coupon. You'll get a FREE school catalog plus complete information on independent home study. For your convenience, we'll try to have a CIE representative contact you to answer any questions you may have. Mail the card or the coupon or write CIE (mentioning name and date of this magazine) at: 1776 East 17th Street, Cleveland, Ohio 44114.

Patternshown on oscilloscope screen is simulated.

r--------------I C I E Cleveland Institute of Electronics, Inc. I 0 YES ... electro~ics-CI~, I I I I o I MAIL TODAY I 1776 East 17th S t r e e t , Cleve land, Ohio 44114 Accre dited Member National Home Study Council

I want to learn from the specialists in Send me my FREE CIE school catalog plus my FREE package of horne study information. RE-95 Print Name: _ Address




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CD 00



New equipment overflows malls of Cable TV convention As expected, the 1980 National Cable TV association convention served up a cornucopia of new satellite equipment. The CATV industry has led the way skyward in video programming-and this year's record-breaking gathering indicated that the boom in cable/satellite networking will continue. Not only were there numerous announcements about new programs, but we also saw dozens of new products, including a number of low-priced receivers that seemed more attuned to amateur use for at-home reception. One item that generated considerable interest (along with jibes about its creating a need for satellite-dish termite exterminators) was a $750 12-foot antenna built on redwood strips; the antenna kit includes a spherical aluminum screen reflector on the wood struts. Although a working model of the device was not on display, its builders say it does pick up a good signal; it's made by Vidiark Electronics, Box 9363, 3765 South Third Street, Memphis, TN 38109. Small dishes were the order of the day at the NCTA convention, with such companies as Compact Video Sales (1100 West Chestnut St., Burbank, CA 91506) and familiar giants such as Gardiner Communications, Scientific-Atlanta, and Hughes demonstrating dishes under five-meters across. Hughes also introduced a device that can be added on to an existing antenna to improve its reception capability . Prodelin (PO Box 131, Hightstown, NJ 08520) unveiled its new segmented fiberglass antenna, which is now available in a 10-foot model for $2,450. Each of the eight petals of the 10-foot model weighs under 15 pounds, which could pave the way for more affordable tracking systems . Lindsay introduced a 12-foot TV receive-only earth terminal that uses high-tensile aluminum-petal construction. (Lindsay Specialty Products, 50 Mary Street West, Lindsay, Ontario, Canada). U.S . Tower Company (PO Drawer S, Afton, OK 74331) demonstrated its new 3.3-meter dish, priced at $2,275 including all mounting hardware. In all we counted well over a dozen dishes on display in the walkways and parking lots surrounding the convention center. Inside the convention hall there were scores of satellite video receivers on display . Rockwell International's Collins Transmission System division showed three new models of its SVR-4 satellite video receivers, with low carrier-to-noise ratios (such as 8.0 dB for the SBR-OA-I receiver). Other electronic giants, such as Harris Corp., demonstrated new LNA's and video receivers.






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Programming galore Along with the stunning new hardware at the Cable TV convention came a wave of new program announcements. The most overwhelming was the news about Premiere, a new all-movie pay-TV service due to begin operation s in January 1981. Premiere is a joint venture of four major Hollywood studios (Columbia Pictures, MCA-Universal, Paramount Pictures, and 20th Century Fox) and Getty Oil Co., but it will also use films from other studios and producers. Premiere's partners plan to offer movies on their own channel at least nine months before they are permitted to be shown on such existing pay-TV circuits as Home Box Office or Showtime-a plan that has prompted other companies to charge that the whole Premiere concept is illegal, a violation of antitrust laws. Whatever the outcome of those legal snarls, the Premiere plan itself is massive. Not only would there be about 15 new movies

per month offered via the channel, but they would be bounced on at least two and maybe three satellites. Premiere has bought a transponder on Satcom I from Satellite Program Network; that circuit will probably be used for the transmissions to the western time zones. The company has access to a Cornstar D2 transponder and to a Westar III circuit, one of which will be used for East-Coast transmissions or all-day service. Since Getty Oil is a major backer of the all-sports ESPN channel, some of Premiere's programming may share a transponder with the overflow ESPN service (the main ESPN fulltime network remains aboard Satcom I). In addition to the Premiere bombshell, the cable TV convention poured forth dozens of other program announcements. Home Box Office will start a second pay-TV channel called Cinemax, an all-movie channel which will include some foreign movies and older movies. CBS has formed a cable-TV programming subsidiary that will send shows via Westar III to cable sysiems; the CBS Cable line-up will include new programs never used on the regular CBS broadca st network . Black Entertainment Television will carry an expanded line-up of college football and basketball games starting this fall, and GalaVision, the Spanish-language pay-TV network, has already started its new coverage of professional boxing matches . In addition, most of the existing program providers using satellites today offered previews of the additional shows they'll carry during the coming year. There will be a variety of special interest shows, ranging from a Ralph Nader consumer-affairs program on Showtime to a show called "Women" (delivered via a new color-slow-scan video process) on Satellite Program Network. Westar adds more signals There are at least ten new program services traveling aboard the Westar satellites this summer-including the raw program material being beamed into the brand new Cable News Network headquarters in Atlanta. CNN, the latest brainchild of TV maverick Ted Turner, is the 24-hour-a-day news service that began in June. (After a long legal fight with RCA Americom, CNN has won temporary authority-at least through December-to use Satcom I Transponder # 14 to send its all-news programming to cable-TV systems.) However, the programming to Atlanta from CNN bureaus around the country travels via Westar III Transponder II. Meanwhile Western Union has also lined up a number of other customers, including Hughes TV Network with its heavy dose of sports and special programs (Westar III, Transponder 2) and Spanish International Network (Westar III, Transponder 9) . Also on Westar III are CBS (Transponder 6) and ABC (Transponder 10). Satellite Communications Network is on Westar I, Transponder 4. Around the satellite circuit Comsat has formalized its plans for a direct-to-home satellite service; it has created a subsidiary called Satellite Television Corp. that will buy and develop programming for the proposed high-power feed. Comsat is still looking for a retail partner to sell and install the necessary small-dish receivers. And the company recently indicated that it is pushing back its target date from 1983 into 1984. Many skeptics believe that it will take much longer than that for the FCC to approve such a complicated venture. GARY H. ARLEN

Sony Wrote the Book on VTRNow It's on Tapel Until now , learning about video recorders meant poring over very technical textbooks-if you could find them . Or enro lling in a highly specialized school. But with the new Sony Basic Video Recordin g Course, you can easily learn everything about video tape recordin g using video itself as a teaching tool. At your own pace, whenever it's most convenient for you . The Son y course clearly demon strates the theory, operation and characteristics of every major VTR unit . Including EIAJ , Betamax, VHS , U-matic, Quad and SMPTE Types A, B and C. You'll learn everything fro m the fundamentals of magnetism to the sophisticated processes used in color recording. And at the end of each lesson you 'll find a thorough self-review test, so you can be sure you fully understand each subject before going on to the next one. You can or der a preview tape, individual tapes on a specific subject or the entire course in Betamax or U-matic forma t.

COURSE CO NTE NTS : Th e course consists of eight color video cassettes rangin g from 23 to 30 minutes in length and eight supplementary booklet s: 1. ELEMENTS OF MAGNETIC RECORDING, 2. VIDEO REC ORDING , 3. SCA NNE R SYSTEMS , 4. TAPE FORMATS, 5. TAPE TRANSPORTS, 6. SCANNER SERVOS, 7. LUMI NAN CE P ROCESSING, 8. COLOR SIGNAL PROCESSING. The Sony Basic Video Recording Cou rse will make you an expert on video tape recording. Whether you alread y own, sell or service video equipment or just have an electronics background and want to understand how it really works-this course is what you've been waiting for. It would be hard to find a better teacher than the leader in the field- SONY.

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%" U-matic D $487.00 These prices available for limitedtime only. (Reg. price $623. (0) INDIVIDUAL LESSONS (price per cassette/ booklet) Betamax 0 I hr. 0 2 hr. $61.00 %" U-matic D $76.00 Circle lesson # and indicate quantity desiredin space provided. ~ , ~ , 3__,4_ _ .5_ _, 6_ _,7_ _,8_ _, PREVIEW TAPE Betamax 0 I hr. 0 2 hr. $12.50 U-matic 0 $28.00 Add appropriate salestax and $1.75 per cassette ($14.00 for complete course) for handling and shipping. (UPS in continental U.S. If outside, add $15.00 for export charges, plus collect freight charges; special handling is extra.) Make check or money order payable to Sony Corporation. If charging to your Sony account, fillin number and enclose purchase order. _ For phone orders, call: (213) 537-4300 Ext. 474 or visit your local Sony dealer. .

We honor VISA or Master Charge via phone or mail. Name


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SONY.VIDEO COlVl:M:UNICATIONS Sony, Betamaxand Ll-matic are registered trademarks of {heSony Corp.




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61 Service locations throughout the United States and Canada Hea thki t Electron ic Centers in th e U.S,· a nd Ca na d a a re lis ted in phon e d irectory w h ite p ages . "Uni ts of Veri technology Ele ctronics c orp or a tion.


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cate .003 watt! In this modification, the meter is converted to a single-channel , 20 LED meter, and thus, two are required for stereo. The modification requires replacing R20 with a 1200 ohm, 5%, resistor and R21 with a 4,870 ohm resistor (the previous value of R20), eliminating R15, R17 and the left channel inputs, and rewiring (Fig. 1).

The Audio Power Level Mete r (February, 1980 issue) can be modified to show about twice the dynamic range (55 dB) for those who like "dancing lights" down to background power levels. With 55 dB dynamic range, if the top LED is calibrated to indicate 100 watts, the bottom LED will indiRI

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This modification should work with amplifiers capable of 40 watts or more per channel. R2 is still adjusted as described in my article. Adjust R16 by playing music that lights up between 8 and 12 of the LED's and adjusting for a smooth transition from the 10th to 11th LED. (This is hard to describe but easy to do!) The standard PLM-1 kit can only be used with stereo amplifiers whose outputs include a common ground (virtually all commercial amplifiers). Unfortunately, the Talbot amplifier in your December, 1979 issue does not have a common ground between two output channels, and thus can only be used with two independent PLM's, such as those built with this modification. Also, with this modified monaural PLM, one can be placed on top of each speaker in a stereo system, making it easy for the listener to

see. Discussions with readers has shown me that many people don't realize that the pictures of the PLM-1 in my article were taken from underneath. When turned over, the PLM appears to be in a solid walnut case.

continued on page 32

FIG. 1

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The best possible TV reception in al most any area . That's what you r customers will get with RCA's Permacolor Outdoor TV Antennas. One of the reasons is the use of solid , riveted connections of flex ible aluminum from elements to feed line. These permanent connections provide a positive electrical path for the signal to flow . There's no chance of interruption . . . overcoming a major problem found in other antennas. Plus polypropylene insulators and a weather-resistant blue and gold polyester finish contribute to Permacolor's remarkable performance and long life. With RCA Permacolor, you can offer your customers a co mplete line of outdoor TV antennas , including 75


ohm and 300 ohm antenna kits. The RCA name and tradition will assure your customers that the highest quality and performance are built into RCA Permacolor. And they're right. Permacolor brings in a better TV picture for your customers. And a better profit picture for you . For full information, see your RCA Antenna Distributor or write to : RCA Distributor and Special Products Division, Deptford, N.J . 08096, Attn : Sales Promotion Services.



4BG20 SUBURBAN One of many RCA Perrnacolor Antenna models available .

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30 MHz delayed sweep$1,530. LBO-515B is a compact, precision oscilloscope at a moderate price. Using a PDA 4-inch CRT with parallax-free internal graticule, it features 5 mV sensitivity and delayed sweep for viewing and measuring complex waveforms. Also has 120 ns signal delay, trigger hold-off and x-y operation at full sensitivity.

30 MHz with signal delay -$1,100. LBO-520 combines a 11.7 ns rise time with 5 mV sensitivity and 120 ns signal




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Now, for the first time, you can learn all about microcomputers by working with your own production model at home. We'll explain the principles of troubleshooting and testing this remarkable instrument and, best of all, we'll show you how to program it to do what you want. It's the perfect opportunity for you to learn BASIC high level language programming and assembly language programming. Simulated TV Reception Then, to learn how to localize microcomputer problems and solve them, you'll experiment and test with a digital multimeter and other testing gear. But most Important, you get to assemble and work with today's most sophisticated microcomputers, not home-made training devices. We believe this makes learning a lot more relevant and exciting. In fact, production-model equipment is featured in all NTS electronics programs. Our Color TV servicing program boasts the NTS/HEATH digital color TV (25" diagonal) you actually build and keep. In Communications Electronics you'll build and keep an NTS/HEATH 2-meter FM transceiver, along with digital multimeter and service trainer. Whichever NTS electronics program you choose, you can count on working with much the same kind of equipment you'll encounter in the field. Find out more in our full color catalog on the program of your choice. NTS also offers course in Auto Mechanics, Air Conditioning and Home Appliances. Check card for more information.




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1. The NTS/HEATH H-89 Microcomputer features floppy disk storage, "smart" video terminal, two Z80 microprocessors, 16K RAM memory, expandable to 48K. Available in NTS's Master Course in Microcomputers. 2. The NTS/Rockwell AIM 65 Microcomputer A single board unit featuring an on-board 20 column alphanumeric printer with 20 character display. A 6502-based unit 4K RAM, expandable. Available in NTS's Microprocessor TechnologyCourse. 3. The NTS/KIM-l Microcomputer A single board unit featuring a 6 digit LED display with an on-board 24 key hexadecimal calculator-type keyboard. A 6502 based microcomputer with lK of RAM memory, expandable. Availa~le in NTS's Master Course in Electronic and Industrial Technology.

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continu ed from page 26 The PLM-1 kit is availab le from Symmetric Sound Systems, 1608 South Douglas Ave., Loveland, CO 80537 for $42 postpaid. JOE GORIN Loveland, CO

LIGHT John W. Ecklin's letter in the March 1980 issue concerns the velocity of light and other electromagnetic radiation . His statement " t he speed of light is a constant only to the source and may not be a constant to all observers" is interesting. Consider first the Doppler explanation for spectrum shifts . That explanation was developed first to explain the changed

pitch of sound from a mov ing source, and was based upon the fact that the relative velocity between sound and its source varies with the motion of the source. The variation s caused changes in wavel ength to the front and rear which in turn caused the frequency as received to change. When light was believed to be a wave disturbance moving through an ether substance, it was reasonable to assume a similar effect upon the wavelength of light. After the failure of the Michelson-Morley experiment the wave-ether concept was abandoned . Relativity is based upon the postulate that light moves at a velocity which is an absolute constant, regardless of the motion of the source or receiver. If that is correct, the wavelength of ligh t from a moving source must be the same as if the

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source were motionless, and no spectrum shift could occur. Spectrum shifts may result from a change in either wavelength or frequency as received, and neither wavelength or frequency can change under the absolute constant velocity concept. My reasoning suggests the following: A) We cannot reconcile the Doppler explanation and the absolute velocity concept. B) We cannot return to a simple wave concept because of the failure of the MichelsonMorley experiment. Therefore the only concept which will explain both the results of the Michelson-Morley experiment and spectrum shifts is the particle-photon concept of light. Under the photon concept, we may assume that light moves in full accord with Newton's principles of motion for particles of matter. If so, the addition-of-velocity principle will explain spectrum shifts as due to changes in velocity which change the frequency of light as received. Also when the Michelson-Morley experiment is re-analysed, assuming that light moves as a particle, the failure to detect an interference pattern is in agreement with the part icle concept. Measuring the velocity of light photons is not sufficient to test this matter; what is required is an experiment which will compare , simultaneously, the speed of light from a stationary and a moving source. M. J.IRESON Sechelt, British Columbia, Canada

FCC CERTIFICATION Regarding the article by Greg Grambor entitled "SerVicing Communications Equipment" (May Issue). Mr. Grambor is under the assumption that there is a "required-by-Iaw frequency and modulation certification " that must be performed yearly. What he does not realize is that on September 9, 1976 the Federal Communications Commission put into effect the deregulation proposal of Docket 20665, which eliminated required annual measurements of transmitter power, frequency and modulation. The responsibility of keeping the equipment in compliance with FCC specifications now rests entirely with the user, allowing him to decide when to check the equipment. So contrary to Mr. Grambor's statement, each radio will not generate at least one service call a year . STEVEN L. NELSON Webster, MN

MORE Types· MORE Ratings MORE Quality· MORE Value Sprague Q-L1NE Capacitors are on display for self-service purchasing at leading electronic distributors. The buying is easy because you can see what's available ... without waiting, without asking, without searching ... all pertinent information is clearly spelled out on attractive, color-keyed Blister-Pak packaging, which keeps capacitors visible while protecting them from moisture and dirt. Q-L1NE Capacitors give you a broad choice of popular, frequently-needed types and ratings: Number 01 Ratings

Capacitance values

Working Voltage Range

Axial-Lead Electrolytic


.47 to 15000 f.LF

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Vertical-Mounting Electrolytic


.47 to 4700 f.LF

0-16 to 0-630 V

Vertical-Mounting Film


.0010 to .47 f.LF

0-100 to 0-1600 V

Resin-Coated Solid Tantalum


.1 to 680 f.LF

0-3 to 0-50 V

General-Application Ceramic


5 pF to 3.3 f.LF

0-25 to 0-1000 V

Epoxy-Dipped Mica


10 to 1000 pF

0-500 V

Capacitor Type




With apologies to reader Nelson and others for my coming across a bit of stale source material, I stand corrected. However, it is important to note that, in principle, the idea of every piece of communications equipment generating at least one service call per year remains the same. In the words of Mr. Mannino, the gentleman I interviewed for the article, ", . . any good contractor will advise his customers to have a frequency and modulation check done annually, even though no longe r mandated by law. It is both in the interest of the license holder, and good business for the service shop. " - Greg Grambor


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For detailed definition of types and ratings available, write for a copy of Q-L1NE Capacitor Listings to Sprague Products ce., Distributors' Division of the Spragu e Electric Co., 81 Marshall St., North Adams, Mass. 01247.


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CIRCLE 38 ON FREE INFORMATION CARD a subsidia ry of GK !~!!,nologies

EINSTEINIAN IMPOSSIBILITIES In reference to the letter by Anthony Hans Klotz on page 22 of the Ap ril 1980 issue: Mr. Klotz has expressed a very com mon misconception of Dr. Einstein's theory

continued on page 36

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The Industrychallenge: Make it smaller. Make it better. Make it cost less. How Non-Linear Systems has done it for three decades.

The new Touch Test 20 DMM weighs on ly 2 Ibs. 4 oz. Yet it puts twenty key test fun ctions at your fingertips. Plus exclus ive light pressure touch function selection. Shown fro m above on leathe r shoul der sling (optiona l).


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When we set out to develop the Age by introducing the first digifirst digital voltmeter, the new tal voltmeter. Suddenly and Touch Test 20 digital multimeter ingeniously, data was translated and the new MS-230 miniscope, into the universal language of we knew it wo uldn't be easy. But numbers on easy-to-scan readwe were n 't lo o kin g for easy out panels. answers. We were looking to do With this single idea, NonLinear Systems set two bold it right. That's why, for nearly three precedents . It made clumsy decades, innovation has come analog systems a thing of the first at Non-Linear Systems.And past. And it committed the comwhy our contributions to the pany to first rate value and perfield of electronics have been so formance through sophisticated, far-reaching . yet simplified electronic test tools. First DVM to see the light. In The remarkable Touch Test 20 1952, Non-Linear Systems pro - DMM. With the Touch Test 20, pelled electronics testing out of Non-Linear Systems introduces the Stone Age into the Space the 2 lb. 4 oz. test lab. Now, with

20 key test functions at your fingertips (plus the ability to measure 10 electrical parameters and 44 ranges), you can take one lab to the field instead of a cum be rso me collec tion of in dividual testers. Anot her bright idea.The Touch Test 20 is the only DMM with lightpress ure touch function selection. No more dials to fiddle with. Instead, 'an LED shows the function you choose. And when you switch, you get an audible bleep and visual blip to let you know. This small wonder is miniaturizatio n at its bes t. The new Touch Test 20 is the m ost innovative portable/bench -type multimeter in the industry today. Or, you can choose from NonLinear Systems' eight other

Remarkably light and ve rsatile . the Touch Test 20 DMM is perfec t in-shop or on-s ite.

sophisticated DMMs. And rest assured that you'll be getting the kind of performance and value packed instrument we've been making for nearly thirty years.

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continued from page 32 of Special Relativity. Radio-Electron ics, unf ort unately, has given credence to tha t misconcept ion by allowing Mr. Klotz 's letter to appear wit hout comment. May I explain? A woman sta nds beside a highway . A man in an auto dri ves past her at a const ant speed . The speedometer in the auto indicates 60 mph. The woman, lo ok ing at the auto, sees it zip past her. The man, looki ng out the window of the auto, sees a wom an zip past him. Which of those two obse rvers is cor rect? The wom an says an auto dr ove past her at 60 mph . The man says he looked out the

window of the auto and saw a woman zip past him at 60 mph. In everyday life, we automatically assume that it was the woman who was at rest and that the man in the auto was the one in motion. In our day-to-day affairs, such as assumption causes no difficult ies, However, when such an assumption was exte nded to the realm of atomic particles, with their sma ll masses and very high veloc ities and energies, the assumption rapidly caused severe problems and obvious miscalculations. What to do? Dr. Einstein provided the answer . He showed with mathematical precision that both the man and the woman are equally cor rect . It is no more correct to say that t he woman was still and the auto in mot ion t han it is to say that the auto was sti ll and




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the woman zippe d by, unless . . . Unless a th ird , independent observer is introduced. For example, an astronaut on the moo n migh t look at the man and woman (imagine he has a super-te lescope) and say: " Yes,. t he wo man is standing on the eart h and t he man in the auto is moving over the earth 's surface ." Thus t he motion of the man and woma n must be judged telative to an observer. Even then, the motion is only relative to t hat one observer. For example, if the man and the woman were jud ged by a pil ot flying a helicopter at 90 mph in a direction opposite to that of the auto, the pilot 's observation would be quite different from t hat of the astronaut . (The pilot would have to say that the woman was moving past him at 90 mph, while stating th at the ma n in the auto was passing him at 150 mph .) Return ing now to Mr . Klotz's letter, which conce rns ligh t beams mov ing relative to two obse rver s, with one obse rver moving and the other at rest - Mr. Klotz comes to the conclusion that Dr. Einstein's logic is invalid . But the argu ment is deficient in two respects. First, Mr . Klotz cannot have two movi ng obs ervers (a reference frame, and M' in his not ation) without an additional obser ver to whom such motion would be relat ive. To spe ak of a "moving reference frame" is self-co nt radict ory, as the refe rence fram e, by definition, is arbitrarily considered stat ionary, in ord er to judge the mot ion of the ot her objects. If a reference frame is indeed t hat, and is also assumed to be in motion, t hen two separate problems are being comb ined invalidly. Mr. Klotz's second deficiency is in the use of light beams in a cont radi ction of simultaneity. Dr. Einst ein had t heorized that t he speed of light is a universal constant. It is t he same relativ e to any and all observers. In one of the mos t famous experiments in all physic s, Dr. Al bert Abraham Michelson confirmed that th eory: It is an experimental fact. To appreciate Dr. Michelson's work, assume that two spaceships are rushing toward each other at % the speed of light. One of them is emitt ing a beam of light while the ot her tries to measure the speed of t hat beam . Now assume t hat the tw o spaceshi ps are rushing away from each other at '/. the speed of light, and again one emits a beam of light while the ot her measures its speed . What results are ob tain ed? One mig ht assume t hat the measuring spaceship would measure t he light beam at 1'/. times the speed of light when the ships are appr oaching, and at % the speed of light when they were retre ati ng. Not so. The speed of light would be read exactly the same in both cases. As said, experimenta lly confirmed . Perhaps the sim plest way of putt ing it is t his: When Dr. Einstein published his famous papers, it was the year 1905. The ideas he presented therein were called theor ies. It is sti ll common to refer to them as " theor y," though most all of them have been con firmed tim e and again by direct exp erime nt . Indeed , no mod ern atomic par ticle accelerat or could fu nction unless its design took Dr. Einstein' s "theory" into account. ED EDWARDS Midland, MI R-E

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The Defender TS-1 CB Antenna Tuner/Monitor


station may possibly be the antenna system. There seems to be a general idea that if you go out and buy a new antenna designed for operation on all 40 channels, then you should expect equal efficiency at each channel chosen for your favorite operation. Not so! In most cases an antenna can operate at its best on only one particular channel and as one moves farther and farther away from that design point, there is a loss of efficiency. That has been noticed

especially in mobile units when checking for proper tuning of the antenna and you have found it difficult to get a good SWR reading across the entire band. In .most cases you have had to accept a compromise adjustment. The Defender TS-I is designed to allow you to squeeze every last bit of power out of your base rig. It operates by making it possible to adjust your antenna system to the point of optimum match with your ' transmitter. In other communication fields, that type of unit has been called by various names but it really is an antenna tuning unit. There have been some "add-on" items available for CB, but the Defender has built the tuner into an attractive wood-grained cabinet. In addition to the antenna tuner, the TS-I also contains a built-in power meter capable of operation on either 5 or 50 watts, an SWR (Standing Wave Ratio) bridge, a modulation meter, and a handy antenna selector switch . The Defender is manufactured by The Shakespeare Co., Inc., Columbia, SC 29202. . In operation, the Defender is connected to the CB rig through a short piece of 50-ohm coaxial cable and the station antenna is connected to either one of the two antenna connec-

tors on the rear panel of the unit. The unused connector can be terminated in a dummy load (supplied with the TS-I) or to a secondary station antenna. At that point, all further adjusting or measuring is accomplished with the front panel controls . For instance, if you wish to check the power output of the transmitter quickly, all that need be done is to set the antenna switch to the position the dummy load is connected to, press the button marked POWER, and read the output power directly on the meter face. Calibration is from 0-5 watts . By setting the antenna selector switch to the position that connects the antenna to the rig you are now ready either to check the SWR of the system or to continue communicating. Assuming that you would want to test the SWR, all that is required would be first to press the FORWARD button, and adjust the METER ADJUST control for full-scale reading on the meter while keying the transmitter. Then press the REVERSE button (still holding the transmitter in the keyed position); the meter will now indicate the SWR value. The center scale is used for that measurement and is coded in bright red when the SWR exceeds 3 to I. Of

continued on page 40

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continued from page 38 course, if you are using two (2) antennas connected to the DEFENDER then you could press the selector switch and check the SWR of the secondary antenna. The SWR reading is a good indicator of the efficiency of your antenna system . The Defender will also allow you to tell at a glance just how much "talk-power" your rig is delivering . That function is accomplished by the built-in modulation checker . While keying the transmitter but not talking, press the SET button and adjust the METER ADJUST control for a reading of 100% on the meter. Now, by pressing the TEST button and speaking into the microphone, you will note that the meter will indicate a reading that should increase the

louder you speak. The percentage of modulation is checked by using the bottom scale of the meter. Remember, whenever you exceed the 100% reading while speaking into the microphone, your audio quality will be degraded, and distortion will be noticeable on your signal. The Defender operating manual suggests that you constantly monitor the percent modulation at all times in an att empt to keep your voice at the level that will provide the best talk-power on the air. And now, we come to the antenn a-tuning capabilities of the Defender TS-I . To make your antenna sytem present the best load possible to the transmitter, tune your rig to the desired channel and depress the SWR REVERSE button. Set the ANTENNA MATCH switch to the IN position, key the microphone (don't speak) , and adjust the TUNE control until a reduction

in the SWR reading on the meter is noticed. When you have found the point of minimum reading, adjust the LOAD knob until once more the reading on the meter is at minimum . By repeating each of those two adjustm ents-the TUNE and the LOAD controls-until no further reduction is obtained, you may get close to a perfect l-to-I match. To check, measure the SWR and you may be happily surpri sed to find that it is much lower than that which was previously measured on that particul ar antenna. The match will be best only at the channel in use when you tuned the antenna . If you change the operating frequency (channel) then you should either place the matching switch in the OUT position, or, retune the system to the new channel. It should also be pointed out that the adjustment for one antenna will not usually be the same for another antenna. Each time the antenna is changed or there is a switch in the operating channel, to keep the system at optimum, the tuner should be readjusted. In the model supplied, there is a toggle switch located on the rear panel which allows the Defender to be used to make readings up to a maximum of 50 watts of RF power. There are instructions provided for such use. However, all other measurements and checks must be made at 5 watts only. The Defender TS-I is covered by a I-year limited warranty from the manufacturer. It has specifications that include SWR measurements of 3 to I and over, power output measurements of 5 and 50 watts, modulation to 125% can be checked and the antenna tuner can match a 4-to-1 system to provide an SWR of 1.5 to I (or less). In an actual test of the Defender. we were able to match two different antenna systems that initially had SWR readings of almost 3 to I. We obtained an almost perfect match for both antennas. It should be noted that your system may vary from what we obtained. However, if the SWR in your system is reduced by even a small amount, there can be little doubt that your system is providing a more potent signal. And , isn't that really what you are attempting to do in the long run? R-E

lET Model RCS-SOO R-C Substitution Box


of trial-and-error component substitution by the "one-at-a-time" connect and disconnect method will appreciate the convenience of the Model RCS-500 resistance/capacitance substituter from lET. The RCS-500 is actually a combination of two separate resistance and capacitance substitution boxes available as the models RS-200 and CS-300 .

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continued f rom page 40 T he substit uter features thumbwhee l selection of values, independently obtained from either the resistance or capacitance side of the instrument through separate termi nals. Th e real beauty of such an instr ument is, of course, the capability of dialing in virtually any resistance or capacitance imaginable. The resistance portion of the box is accurate to I%. All resistive components are Ij,-watt units, serially tied, allowing for a selection in l-ohrn increments from I to 9,999,999 ohms. Residual circuit resistance is 0.4 ohms. The resista nce thumbwhee ls are conveniently separated and labelled as ohms, kilohms, and megohms. T hus, no mental gymnastics are necessary- merely dial it up and read it!

The capacitor portion of the substituter is just as simple to use. The th umbwheel switches on that side of the instrument are labelled in microfara ds, nanofarads, and picofarads. Capacita nce selection begins at 100 picofarads, incrementa lly advancing in IDO-picofarad steps to a maximum value of 99.9999 microfarads. All capacitors below 10 microfarads are rated at 100 volts; those above 10 microfarads will tolerate 25 volts. Capacitors are parallel-tied, with a residual circuit capacitance of 30 picofarads. Capacitors in this section are specified at 4% tolerance. We decided to check their actua l values to see whether they are really that close. Electrolytic capacitors are especially notorio us for drifti ng away from their rated value, and electrlytics are typically rated below their actual capacitances.

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Checking the specifications The instrument we used to check the capacitors was lET's own CM-500 autoranging digital capacita nce meter, certified earlier as being accurately calibrated. Below 10 microfarads, the capacitors in the RCS -500 were well within tolerance, with most measuring ± 2 to 3 percent. At 10 microfarads and above, tolerance fell back a little, as was expected, to ari accuracy of between 7 to 8 percent. St ill, that is bette r than the usual + 50% found on many electrolytics! Internally, the circuit-board assembly and layout shows the care we have found to be typical of lE T craftmansh ip. The cabinet is high-impact plastic, heavy-duty thickness, and all functio ns are clearly labelled. The mode l RCS-500 measures 7.40 X 4.33 X 2.36-inches and weighs a mere 14.5 ounces. While the R CS-500 (or the separate resistance and capacita nce boxes) are certainly adequate for th e vast majority of applications found in servicing and prototype design, a new series'of tig ht- tolera nce subst ituters has been announced. Th e RX-201 resistance box uses 0.1% resistors, while the CS-301 capacitance box features I% capacitors . But for most of us, the accuracy of the RCS500 resistance/capacitance substitution box is more than adequate. Remembe r that when you use a substitution box certa in precautions must be taken: Voltage ratings for the capacitors must not be exceeded; nor should switches be continually flipped among high-capacitance values which are connected across B + . That will produce arcing which could grad ually break down the contact surfaces of the thumbwheel switches. Also, don't forget that excessive curre nt-flow thro ugh resistors will cause them to heat up, often permanent ly changing their resistances if not totally destroying them. Properly used, an R-C substitution box of the quality of the lET unit will offer years of tro uble-free service. The RCS-500 digital resistance/capacita nce substituter sells for $185.95. For further informatio n, write lET Labs, Inc., 761 Old Country Road, Westbury, N Y 11590. R-E

Datong Model AD-170 Active Antenna

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used active ante nnas for years. Recently, their high performance and reasonable cost have caught the attention of many shortwave listeners. Several manufact urers now offer variations on that unique antenna principle. Datong, a British firm, offers the Mode l AD-J70 indoor receiving antenna system that is designed for continuous coverage from 60 kHz through 70 MHz . It consists of several intercorihecting parts: anten na preamplifier, wire dipole elements, interface unit, interconnecting cable and power supply. In application, the wire dipole is suspended

hor izontally as high as possible indoor s. An att ic space, away from electrical wiring or met allic mass, is ideal. T he man ufactu rer advises th e user to experiment wit h a number of mounting configurations, both in dire ction and polarity. In some cases, vertical mounting of th e eleme nts will ' work bett er than horizontal mo unti ng. Th e AD-170 is designed to feed its signal into a receiver's 50-o hm ante nna inpu t. An AC ada pter th at comes with the unit sup plies 12volts DC at 120 rnA . Th e ante nna prea mplifier is not wate r proof, so a pro tecte d installation is required. T ransmission line length is only 15 feet, requiri ng indoo r use. Int ern ally, the AD-170 is nicely laid out. Com ponents are carefully hand soldered onto a glass epoxy circuit boar d. Spec ifications of the ante nna system are impressive. Thi rd- order inte rmod ulation products are typ ically - 90-dB relati ve to 100 m V. Seco nd-order int er modul ati on dist ort ion is - 80-dB re lat ive to 50 mV. Response is essentially flat over its opera ting freq uency range. Th e received signal "sees" th e AD-170 as a high-t o-low impeda nce converte r, capaci tively coupled to the signal as 12 picofa rads. A switc hable preamp lifier allows an addi tional 12-d B gai n that is to be used for weak signal reception. Alt houg h. the A D-170 is very short (10 feet dipole length ), it is equivalent in perfo rmance to a fu ll size 16 MHz half-wave dipole. At higher frequ encies, per form ance increases at the rate of 6 dB-per- oct ave. Below 16 MHz th e gain decreases at th e same rat e, 6 dls-peroctave as compared with a full size half-wave dipole at the frequency of inte rest. It is easy to see that alt hough the respo nse of the AD - 170 is down 18 dB at 2 MHz, a full size 2-M Hz dipole would be 250-feet long. T his much wire is enti re ly unnecessary to capture adeq uate signal for modern high -sensitivity shortwave receivers. In fact, broadcast-ban d inte rference would create a real problem wit h interrnodulation in most cases. An antenna needs only to be long enoug h to prese nt a sig nal of high enoug h inte nsity to override syste m noise. We decided to test th e overa ll performance of the AD-170 against a 66-foot refere nce dipole. Th e dipole was approxi mate ly 15 feet above the soil and the A D-170 was mounted only 8 feet high. Both ante nnas were mounted in th e same directi on to cancel direct ional effects. A McKay-Dy mek DR -33C receiver wit h a calibrated S-meter was used as the broadband receiver. T he ante nnas were switched through a Daiwa CS-20f U HF coaxial antenna switc h. Th e receiver was tuned to doze ns of signa ls th rough out the 100-kH z to 50- M H z range. In virtually every case, the A D-170 was clearl y superior to the dip ole, ofte n by 10 or 20 dB, sometimes more. Th e only tim es that th e large reference dipole was ahea d was when it was receiving signals near its self-reso nant frequency, and even then the diffe rence was only about 5 DB.

Use it as an RDF As an experiment, we connected two 5-foot length s of lightweight alumi num rod to the pream plifier. Th at dipo le was then rotated while monitoring a variety of signa ls thro ughout the spect rum broad cast through CB. Th e dir ecti onal effects were quit e pro nounced. Varia tions on th at arra nge ment will probab ly occur to readers who are interested in erec ting a wide freq uency coverage direction-find ing an tenna. Th e system would also be valuable for

nulling out interference. We would recommend two improvements to the manufacture r. One would be the availability of a coaxial-cable extension so that the line can be run less directly for cosmetic reasons. Connectors on the interconnecting cab le are European, and difficult to find in this country. T he second would be a weat herproofing kit consisting of a plastic housing for the litt le prea mp lifier and its terminals. We found the AD-170 to be thought fully designed, competently engineered, and reasonab ly priced . For th e apartment dwelle r, or for the SWL who doesn't have an enormous amount of rea l estate to erect a large dipole, an active antenna like the A D- f 70 is hard to beat. The AD -170 active antenna system sells for $89.00. Available from Gi lfer Associates, P. O. Box 239, Park Ridge, N J 07656 . R-E


to realize that prematur e death might be lar gely avoided if a cer tain num ber of telltale signs were heeded. Th ose "risk facto rs" includ ed, among other th ings, obes ity, smoking, stress , and blood pres sure . It is a well esta blished fact that high blood pressure (hyper te nsion) is a major cont ributor to a shortened life span. Fortunately, it is easily diagnosed; unfortunately, too few Amer icans both er to have it checked . Traditionally, blood press ure (BP) is tested by a gadget with the fancy name, sphygmoma nometer. T hat is the familiar inflatabl e cuff

continued on page 44


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New Continuity and Voltage Testers With Exclusive Features You Really Need Order your tester today by simply filling Up untilnowvoltage and co ntinuitytesters very ofte n did more to test you r pa tie nce out the convenient form below . Be sure to than they did voltage. Dimly lit, hard to see indicator lights - fragile bodies that eas ily indicat e the total number of testers ordered cracked or sp lit-poorly des igne d shapes that brought finge rs in touc h with live co n- and the total amount enclosed . Send to: PALADIN CORPORATION tacts - bulbs that burned out Quick ly or ne ed ed to be change d for higher voltages. 31332 Via Colinas Now Paladin introduces the next ge ne raWestlake , CA 91361 tion of testers that can e liminate the s e and PALADIN (213) 991-4970 a ll of your oth er testing problems. Palad in products are diffe rent. SEE THE DIFFERENCE- The PA1751 '1 Voltage Tester and PA1752 ContinuityTes te r Please send me: feature bright, ea s ily read LEOs that ha ve _ _ PA1751 Voltage Tester(s) te n times the s ervic e life of incan des cent @ only $ 19.95 each . _ _ PA1752 Continuity Tester(s) bulbs . @ $18.50 each . Thes e testers featu re true ac/dc voltage I and continuity measurement capabilities . Grand total enclosed $ _ FEELTHE DIFFERENCE - The s e Paladin (Add $2.00 for postage, handling ; Tes te rs are molded from tough, durable Calif. residents add 6% sales tax) plastic that ensures their co ntinued operation Bill my 0 Mastercharge 0 VISA in a ny working e nvironment. Allof our testers have a specially designed finger guard that Card acco unt # _ prevents the use rfrom inadvertentlybecoming Signature Exp. Date_ pa rt of the voltage test. EXPERIENC E THE DIFFERENCE- The Name _ PA1751 a nd PA1752 Testers are unmatch ed for performanc e a nd econo my by any othe r _ Address testers on the market. At only$19.95 for the City State Zip_ _ PA1751 and $18.5 0 for the PA175 2 you' re not s pendin g more-you're just getting more .






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continu ed from page 43 aparatus found in every doctor 's office, ambulance, clinic, dentist' s office, and even some American homes as well. It works in a manner similar to a barometer. The inflated cuff blocks circu lation in an artery of the arm, and the meter indicates the amount of pressure necessary to cause the stoppage.


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We just knocked down the last reasons for not going digital in a multimeter. Fast continuity measurement. And price. Beckman 's exclusive Insta -Ohms> feature lets you do continuity checks as fast as the analogs . And Beckman's superior technology and experience let you own this beauty for such a reasonable price. Of course you get a lot more . Like 7 functions and 29 ranges including 10amp ac/dc current capability. 0.25% Vdc accuracy. In -circuit resistance measurements and diode /transistor test function . Two years' typical operation from a common 9-volt battery. In other words, all the features you want in one hand-held unit of exceptional good look s and design. With 1500 Vdc overload protection, 100010 instrument burn-in, plus rugged , impact-resistant case, you're assured of the utmost in dependability and long-term accuracy. You get a tough meter that keeps on going, no matter how tough the going gets. So visit your dealer today and get your hands on the DMM that does it all. Or call (714) 871-4848, ext. 3651 for your nearest distributor.




o Ci «a: 44


Each time the muscular lower chambers of the heart contract (systole) , the forward surge of blood builds up pressure in the arteries. Between beats (diastole), the pressure drops lower. A comparison, or ratio, between the sys. tolic and diastolic pressures is the familiar fraction used to indicate blood pressure . An average, healthy adult might show a blood pressure of 120/80. This means that during the increased pressure of the heart beat , the pressure in the vessel is equivalent to a column of mercury 120 millimeter s in height. Between beats, the pressure drops to an equivalent of 80 millimeters of mercury . In fact, the older sphygmomanometers used a column of mercury as the indicator . Most present-day blood-pressure measuring devices display their measured pressure on a calibrated dial. That instrument is similar to an aneroid barometer. The use of any conventional blood-pressure tester requires a two-step procedure. First, the cuff has to be wrapped and inflated. Second, a stethoscope is required to detect the cutoff pressure so that the readings can be taken. It is very difficult for an individual to measure his own blood pressure when working under such an arrangement. Now, Micronta has released a "do-it-yourself ' blood-pressure tester available from Radio Shack . The pressure cuff is still there, but it is equipped with a buckle and Velcro combination that makes one-arm application easy. A white dot on the cuff shows the proper location for the artery at the elbow joint of your arm. Under the dot, a small pressure transducer monitors the blood pressure, signalling the electronic circuitry in the instrument. As with older stetho scope units, the cuff is inflated until arterial pressure no longer supplies an increase of systolic pressure. On the Micront a BP-I, that is indicated by an audible "beep" as well as a flashing red LED . A thumb-operated pressur e-release button is then activated to reduce pressure until the beep is no longer heard, and the light ceases its flashing; that indicate s diastolic pressure. Those two points are read on the gauge, and recorded in the usual fashion. A handy printed

continued 011 page 84

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Right Out Of Electronic Counterintelligence.

THE HIERonvmus mACHinE,"

Uolce Stress Computer

It's al most beyond belief . Thistiny solidsta te Instrument measures 3" x 6" x11h" and 'fits In a pocket. Yet it contains soph istic a ted electronic c ircu itry, a mic roph one, and three red diodes. It a na lyzes the human voice for stress. Once you lea rn, in about 30 minutes , how to use the Hieronymus Machine, you will be able to discover whether a person Is c a lm or stressful - merely by monitoring his or her vo ice. DEFINITELY NOT A "LIE DETECTOR"


The Hieronymus Machine Is not a lie detector. Nor Is It a "truth" device. Even the famed polygraph machine Is not a lie detector, p lain and simple. The polygraph can be used to monitor a person's p ulse, respiration, b lood pressure , a nd galvanic skin response, bod ily func tio ns affected by stress. And In the hands of a skilled operator, the polyg ra p h can be used to ga in Insights about a person's stresslevels when talking about certain topics. But a very real p a rt of the polygraph's usefulness Is the "Hieronymus Effect," which we'll gel to In a moment. SPIES AND COUNTERSPIES

During wartime, counterintelligence experts wondered If science could come up with someth ing simp ler than the polyg ra p h to he lp ferret out spies . Researc hers became attracted to the theory tha t human voices emit " mlc rotrem ors," low-freq uen c y vibrations that are g en erally Ina udible or masked by other vo ic e components. An art ic le In Popular Electronics (April 1980) descr ibes the theory In detail. But the short story Is that after spending million s of dol lars, researchers d evel oped a voice stress analyzer. Now, the a uthors of the definit ive article In Popular Electronics have perfected a p erson a l vo ice stress ana lyzer, which we call the Hieronymus Machine. WHAT IT DOES, HOW YOU USE IT CI)

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Ci -c a: 46

The Hieronymus Machine electronically measures changes In voice rnlcrotrem ors. The reed-c ut Is simple: one red d iode Indi c a te s normal, two show modera te stress, and three reveal greater stress, ranging from mild to severe anxiety. You , as the operator, could use the Hieronym us Machine like a thermometer, c hecking the "fever level" of stress. As you gain skill, your judgment will lrn-

prove, enabling you to pursue or avoid a line of questioning or discussion that produces stressful responses . MANY USES AT HOME OR WORK

asked about office theft became very cooperative In answering questions truthfUlly. Naturally, YOU'll want to use the Hieronymus Machine In p lain sight and tell people what It does. This actua lly gets more cooperation from them.

You can use the Hieronymus Machine at home to have fun with your family. You'll discover how It responds to d lf· 3D-DAY TRIAL, ferent people's voices, what effect MONEY·BAC K ~UARANTE E laughter and sing ing have on It, and even evaluate polltlcans' speeches over The potential uses of the Hieronymus TVor radio. It works quite well on transmit- Machine ar e limited only by your Imted voices, as well as over the telephone agination . Try It at no risk for 30 days. or with tape recordings. We'll send you one or more with comNext, try It on friends . See how well so- plete Instructions (9v. battery not lnc lud meone's favorite fish story holds up when ed). You'll b e able to try It, experiment, you point out that the Hieronymus even conduct your own " Investigation." Machine doesn't believe a word of It. Governments a nd police departments And watch tha t poker face disappear as and huge corporations are a lready usthe "stress" diode steadily Insists you're Ing la rge (briefcase-sized) versions of this not getting the whole story. kind of machine, and they have to pay $3,000 or so for theirs . Butyou can have a BIOFEEDBACK FOR YOU personal Hieronymus Machine for on ly If you're required to talk In front of $119.95. If you're not satisfied, send It groups or need to speak convincingly to back (Insured) for a full refund, no quesone person at a time, you can use the tions asked. If you want two, the cost Is Hieronymus Machine to monitor your $109.95 each . And If you want three or voice and learn a more relaxed, self- more for bus iness use, It's only $99.95 assured, persuasive style of delivery. If each. You're also protected by a 1-year you wanted to lea rn hypnotism, a relax- parts and labor warranty. ed voice would be a real asset - and EXCLUSIVE BY MAIL FROM MERCURY the Hieronymus Machine could help you The Hieronymus Machine cannot be achieve It. At work, there are numerous situations obtained In stores or from any other In which the Hieronymus Machine cou ld source. To order, send check or money work wonders. Here's how: Hieronymus order to the address below. Or charge It Bosch was a 15th-century painter known on American Express, Carte Blanche, for his startling originality. He was a lso Diners Club, Master Charge or Visa. You something of a medical practitioner, can also call us toll free: and he believed that patients could be cured by passing stones over their bodies . Bosch achieved success because his patients believed that a cu re was taking place. Nearer our own time, a couple of science fiction writers concocted a devise they named after Bosch: It pro- In New Jersey, call toll free 800-322·8650. duced varying sensations In the user Include $2.50 Insured shipping charge depending on whe re a dial was set, from per Machine. N.J. residents p lease add zero to 100. The amazing thing was that 5% sales tax . this ma c hine wo rked on subj ect s eve n Or mall your order to: when It wasn 't plugged In - a perfect Hieronymus Effec t! Now we have a true Hieronymus Machine, the Voice Stress Analyzer. It actually works, and among other things of a scientifically verifiable nature, It produces the Hieronymus Effect. In Its presence, pe op le suddenly become Dept . REg, Lakewood Plaza more forthr ig ht. In some cases, with such a machine p resent, employees being Lakewood , N.J. 08701

800·526·2801 or



Plug-in RenJote Control


LSI technology now brings us armchair control of electrical devices throughout the home. Here's the inside story on how those controllers work. STEVEN A. CIARCIA* " SA VIN G EN ERGY AND SAVING STEPS "

are two of the basic selling points in the advertising for the BSR Model X-JO Home Control Sy stem . In actuality, the features of this unit combine to make the X-lO one of the most ingenious remote control systems yet introduced to the consumer market. The X-lO (also sold under the trade name s of Sears' Home Control System and Radio Shack Plug 'n Power, and in Europe by Busch-Jaeger Electro) incorporates custom-made IC' s that allow the user to tum lights or appliance s on or off from the comfort of an easy chair. Typical applications can include such things as turning on the outside lights, the TV , and the toaster oven--all with just the push of a few buttons . If you are too practical to accept that concept on convenience alone , consider energy and security applications as well. The X- lO make s it easier to tum off extra lights and appliance s when you are not using them. It can tum on all lights in the event of an emergency, tum everything off when you go to bed , or dim light s in orde r to reduce power co nsumption. • Steve n Ciarcia is an engineering consultant and w rites the mo nt hly "Ciarc ia's Circ uit Cellar" and " Ask Byt e " co lumns in Byte, a McGraw Hill pub lication . Copyright © 1980 Steven A. Ciar cia

FIG. l-PROGRAMMABLE TIMER perm its control of lig ht s and app liances without any human interv ention.

The X-10 system components

The X-lO system consists of five separate modules: the Command Controller, Cordless Controller, Lamp Module , Appliance Module, and Wall Switch Module. There is also a new programmable timer unit (see Fig. I) th at provides the sys tem with a semblance of automatic control. The command controller is the central element in the sys tem. It sends command s to the three type s of receiver modules by coded messages sent through the AC powe r lines. The cordless controller is a remote extension of the command controller and has a matching keyboard. When pointed at the command console from up to 30 feet away. any co mma nd that is selected on

it will be transmitted to the command controller and carried out. The commun icat ion bet ween the two units is done ultrasonicall y. Lamp- and wall-switch modules are es sentially the same. They are triaccontrolled on/off switches that include dimmers. The lamp module is plugged into a wall outlet in series with the light to be controlled while the wall-switch module replaces a con ventional wall switch. Those units are rated at 300 watts. For hea vier, or non-resistive load s . a contact-closure-output a ppliance module is used . It is rated at 15 amp s (about 1700 watts). Inside the command controller

Figure 2-a is a block design of the command console. There are two versions of that unit on the market. One has the ultrasonic receiver/cordle sscontroller cap ability; the other hasn't. An internal view of a controller including the ultrasonic circuitry is s how n in Fig. 3. At the heart of that. as we ll as of the other system component s. are custom LSI IC' s manufactured for BSR by General -Instru rnents Corporation . Fully expanded, the BSR system can accommodate 256 independently addressable rece ivers. That is accomplished using 16sets of addresses called " house codes" and 16 "device codes"



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.--. 117 VAC






















22· BUnON t-- - - - - i KEYPAO (SCANNED)

c FIG. 2-FUNCTIONAL DIAGRAMS of a command module, b appliance module, and c remote-control transmitter. Text describes operating principles.

FIG. 3-CONTROLLER MODULE, despite its complexity, is surprisingly small-only 4'12 x 3'12 x 2'12 inches. (/)

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for each house code. The separate house codes allow next-door neighbors to use X-IO's without interfering with each other. A thumbwheel switch on the bottom of the command console sets the 4-bit house code. The keyboard selection determines the channel code. This is shown in Fig. 4 and Table I. In norm al operation the 22-button

HANDHELD remote controller uses a single IC to encode and transmit all commands.

keypad, which is wired as a 3x 8 matrix, is scanned at a rate on.8 kHz . When a button is pressed , its designated function and the house code are combined into a single message. The digital message is directed to the transmitter section where it generates 120 kHz signals that are used to pulse-width modulate the AC line. (See Fig. 5.)

ALL COMMANDS available from maIn console are also found on remote-control keypad .

In order to synchronize the digitallyencoded serial output (pin 15) with the 60-Hz AC line, the circuit must include zero crossing detection. That is done by feeding the AC line into the trigger input (pin 12)where the switching point is detected within 100 microseconds of zero crossing. (Incidentally, pin 13 provides for 50- or 6O-Hz operation .) The transmitted message, now synchronous with the line, is clocked, a bit at a time , on zero crossing. A command message contains 9 bits of information consisting of the 4-bit house code and 5-bit matrix (keyboard function) code. Each message is transmitted in true and inverted format on successive halfcycles of the AC waveform. That is illustrated in Figs. 6 and 7. A logic-I bit is three I-millisecond bursts of 120 kHz signal commencing approximately 200 IJ.S after the zero crossing of each of the phases. A logic-zero bit is represented by no signal for that half cycle . To synchronize the receivers with the transmitter, a trigger code consisting of three successive logic-I bits followed by a logic-zero bit is used . The complete message takes II full AC cycles (183 ms) to complete. Actual attachment to the line is by means of a tran sformer and capacitor coupler. That combination is necessary both for protection and economics. The effective range of this system is generally all the wiring from the controller to the nearest power company stepdown transformer. There are usually five 'o r six houses on each transformer and some coordination with respect to the choice of house codes may be

TABLE 1 House Code






K4 22




K 1 21





K3 20




K6 19






K 2 18





---!.!- HS









128 S3


S2 K


----.! H1 ~ H2


125 S


----!l.. 50 /60





KS 16



FIG. 4-KEYPAD FUNCTIONS and connections to 542C custom IC. Pin 13 of the IC allows for 50 or 60 Hz operatlon•.•at 117 volts AC.

necessary . Also, since the version of the X- IO sold in the U.S. is a 117-volt unit, and most home s derive their 117volt power from both sides of a n O-volt line , sometimes there can be problems in obt aining con sistent operation when receiver module s are used on both the 117-volt lines and relativel y few 220volt appliances are in ope ration to act as a communication bridge. Placement of the rece ivers could require some experimentation . Ultrasonics and the X-10 There is a second method by which PLUG 117VAC 50Hz IN

2200pF 50V



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3.9K 22 pF ':0-



the command con sole designates a contro l function and tran smits instructions. That is through the ultrasonic handheld controller. When a key is pressed, a code is generated and tran smitted as a series of 40 kHz tone bursts. The command console, receiving that information through its ultra sonic receiver section and injecting it into pin 7 of its LSI K', accepts it as if a button had been pushed on the comm and con sole. It then adds the hou se code and retransmits the command message over the house wiring . Figure 8 and Table 2 show in detail

2200pF 50V "

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H1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1

8.2K ~ lOfJF ' 25V GREY




H4 H2 0 0 0 0 1 0 1 0 1 1 1 1 0 1 1 0 0 0 0 0 1 0 1 0 1 1 1 1 1 0 1 0

the communication between the two sub system components. Each of the 22 buttons has a unique 5-bit code . For example, channel 5 would result in a code of 00010 corresponding to bit positions D8, 04, D2, DI, and F respectively. "All lights on" would be 000II. The actual message which communicates that selection is appro ximately 100 ms long and comprised of thirteen 8-ms segments . Each segment consists of a burst of 40 kHz directed to an ultrasonic transducer. A logic-l is a 4-ms burst and a logic-O is a 1.2-ms burst. To signify channel 5 the cordless controller first sends a trigger bit to alert the rece iver in the command console that a message is coming. That is a 40


1/2W 1N4001




H8 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0


FIG. 5-COMMAND CONSOLE schematic allows you to visualize how Information Is encoded and transmitted over AC line. Also shown is transducer for use with ultrasonic remote control. (Courtesy BSR [USA] Ltd .)



ON 4














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OATA OATA -, FIG. 6-TIMING DIAGRAM shows how AC line current is pulse-width modulated to transmit Information from command console to appliance and lighting modules.

1 2 3

4 5 6 7

8 9 10 11 12 13 14 15 16

Clear All Lights On On Off Dim Brighten

FIG. 7-DEMODULATED 120 kHz signals that make up control message.. The three 1-ms bursts signifying a logic " 1" are clearly seen. I+--










MESSAGE ----- -------~



Binary Code 08 04 02 01 F



,I SER IA L ~ OATA ~- -~

Channel Number or Function



d 2.778ms _I





! fL 40 kHZ


4ms 8 ms

0 1 1 0 1 1 1 0 0 0 1 0 1 0 1 0 0 0 0 1 1 0 0 1 0 1 0 1 1 1 0 1 0 1

1 1

0 0 1 0

1 1 1 1 0 0 0 0 1 1 1 1

0 0 1 0 0 1 0 0 1 1 0 0 0 0 0 0

0 a 0 ~ 0 0 1 0 0 0 1 1 0 1 0 0 0





0 0 0 0 0 0 0 0

0 0 0 0 0

0 0 0 1 1 1 1 1 1

already has a pre set house code, that is not sent ultrasonically . The handheld controller is limited to operation on the 16channels of the single house code set on the command console . The se rial-input capability of the X10 is not limited to use with ultrasonic dat a transmis sion . Specific control of the receivers can be accomplished by injec ting a digital command message directly into the serial input pin. At least one personal computer manufacturer is marketing an AC remote-control system using this method. Be advised, though , that the X-IO has a live-wire ground and any attac hment to it should be done through optoisolators.

FIG. 8-ME55AGE FORMAT used by the ultrasonic remote controller. Tone bursts are 40 kHz.


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A PPLIAN CE MODULE interior is tightly packed. The solenoid and 15-amp switch mentioned in the text are at the left of the case ; the AC outlet at right.


kHz tone for 4 ms. Next, the 5-bit matrix-selection code is sequentiall y transmitted as a series of 1.2- and 4-ms bursts of 40 kHz signal. It is followed by a transmission of the logical inver-




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sion of the previous 5-bit selection code and the n a 12-ms "end of message" burst. All messages use the same format-only the 5-bit selection code varies. Also, since the command console

The receivers The receiver end of the system is quite sophisticated considering that each receiver costs less than $17. All recei vers (lamp modules , appliance modules, and wall switch modules) are essentially the same. A block diagram of an appliance modu le is shown in Fig. 2-b. Also incorporating a custom LSI IC , the rece iver section monitors the AC line, waiting for a coded message corresponding to its unique house code (A through P) and unit device code (I through 16). To turn on channel 10, one simply pre ss 10 a nd ON . one after the other. When the appliance module activate s, it sounds like a relay energizing. In actuality, the appliance modules use an inexpensive solenoid to operate a 15-amp snap-action switch . The lamp and wall switch mod ules use a triac instead, and have the capability to brighten or dim in response to contro l commands. The appliance module has only on/off capability. Schematics of the appliance and lamp module s are shown in Figs. 9 and 10.

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FIG. lG-LAMP MODULE can tum on or off, or dim, resistive-load devices up to 300 watts by means of triac (lower left). (Courtesy BSR [USAl Ltd .)

The next step-automatic control Th e X- lO is basically a manual remote-control system. There are however two easy met hods to auto mate the contro ller's activities . One is the BSR model TC-201 automatic timer and the othe r is the BUSY BOX. The BUSY BOX (available from the MICROMINT, 917 Woodmere, NY 11598; 516-3746793) allows an Apple II, TRS-80, or SIDO-based per sonal comp ute r to con tro l the BSR system.

Security while awa y from home, and conven ience while at home, are two of the benefits that may be provided by using the model TC-201 automatic timer. By preprogramm ing on/off times for various light s it is easy to give a hou se a " lived in" look to discourage intruders. The timer has the capacity to control up to eight lights or appliances and incorporates a built-in green fluorescent digital clock. Each module can be programmed for as many as two "on"

and "off" times in a 24-hour period. We have ju st barely scratched the surface of potential app lications for this system. Conve nience is an easy ju stification for owni ng the BSR X-IO but environmental, and energy-management, co nsiderations also co me to mind. In co mbination with a computer, the X-lO ca n bring the concept of computer-controlled living within reach of the average person. R-E



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HOlM TO HOOKUPHOME VIDEO SYSTEMS CATV converters and VCR's aren't always compatible. Here are ways to get around the problem. FRANK GATES YOU HAVE JUST SPENT THIS YEAR' S

vacation money on a new video recorder and you are anxious to get it home and hook it up. The dealer assured you that there would be no installation problems-simply follow the directions , He was right as long as you are hoo king it up to a conventional house antenna or a 12-channel MATV or CATV system. But what happens if you are a pay-TV subscriber or your cable system offers more than 12channels? In both situations, some sort of a decoder or channel selector/converter is required for you to be able to receive those add ition al channels and that is where you start to have installation problems . You will find that if you want to record the pay-TV channel, you will not be able to watch any oth er channel at the same time-which defeats one of the biggest features of owning a video recorder. Or maybe you spent a little more for a programmable video recorder and now you find out .that the converter or decoder defeat s the programmable feature of the recorder. I am going to show you how to overc ome those and similar problems, and at the sam e time get the most out of your home video system.



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What is a converter box? Initially. the most that any cab le system could offer its subscribers was 12 channels. That was due basically to two thing s-line loss with coax cab le limited the cable systems to the VHF range of frequencies (or 54-300 MHz ) and the home recei ver wo uld only tune in 12 of those VHF ch annels. UHF ch annel s we re down-converted to VHF at the cable syste m's antenna

site and then were delivered to the home receiver through the cable system on a locall y unused VHF channel. In short order, all 12 available channels were filled with local VHF or UHF stations. So what happened when the cable systems added more channels? The only way that a home receiver could get tho se additional channels was through the use of an external tuning device, thus the converter box. What that device does is enable the CATV IN 54·300MHz









FIG. 1-CABLE-TV INSTALLATION consists of connecting a converter box between the TV set and the cable . The converter outputs all channels on a preselected VHF channel.

home rec eiver to display the additional ca ble channels without any modification to the TV set itself. It is simply a tun er/converter that enables you to se lect ma nually any incoming VHF ch an nel (54-300 MHz) and convert it to a single co nventional VHF channel on yo ur TV tuner (i.e. Cha nnel 3 or 4). In that mann e r your receiver is able to receive up to 30 or more incoming chan ne ls simply by having the converter installed as shown in Fig. I. With that type of insta llation, the TV tuner is set to the output channel of the conve rte r box (i.e. Channel 3 or 4) and all c hanne l se lecting is done with the converte r itself.


FIG. 2-ADDI'NG A VIDEOTAPE RECORDERto a cable-TV Installation consists of connecting the VCR between the converter box and the TV receiver. With that hookup, however, you must watch the same program that the VCR Is recording.

Now you install your VCR as shown in Fig. 2. That enables the VCR to record any channel offered by the converter box. Again, all of the incoming VHF channels must go through the converter box and they are delivered to the VCR on the output channel of the converter box, let's say Channel 3. (Notice the absence of any UHF connections. Everything has now been converted to VHF . On the front panel of the VCR is a switch that is designed to enable you to monitor all record/playback functions in one position and then switch over and view any of the incoming channels in the other position; thus you have the ability to record one channel and view another at the same time . With the setup shown in Fig. 2, record/ playback will be OK but when you try to view any other channel while the VCR is recording you will find that you are unable to do so. This is because when the converter box is installed,

rv there is only one channel available to _ the VCR. the output channel of the converter box, Channel 3. So when you switch the VCR/TV switch on the front panel to either position, all you can monitor is the output channel of the converter box. Now take a look at Fig. 3. A twoway coax splitter has been added to the system and a simple A/B type switch . That will enable you to record one channel and view any other channel from Channel 2 through Channel 13 at the same time . The way that this is possible is that when you have the A/B switch on the A side you have basically the same setup as in Fig. 2. The A path from the splitter enables you to record any of the 30 or more channels that are available on the cable system, and then while the VCR is recording and the switch in the B position, you are able to view any of the Channels 2 through 13 that are now available to the tuner on your TV set. If you wanted full 30-or-more chan nel capability on the B path of this system. it would require another converter box to be installed between the two/way splitter and the A/B switch. (1 recommend that you spend a few extra dollars and get a good quality A/B switch, one with good isolation; that can save you some headaches in the long run.) What about the decoders? Decoders are what the pay-TV statio ns use to insure that their product is on ly available to those who are paying for it. There are several different methods that are currently being used

by the various pay-TV stations across the country but how they encode and decode the signal does not affect the way that their device is integrated into the home video system. Decoding devices can be treated almost the same as a cable TV converter box! In most cases, the decoder is interchangeable with the converter box shown in Fig. 3. The decoder will have a preselected output channel, probably the same channel as the converter box or the VCR, so the setup in Fig . 3 should overcome any of the same problems that were caused by the converter box. CAlVIN 54·300MHz


FIG. 3-TWQ-WAY SPLITTER AND SWITCH enables you to watch a program different from the one the VCR Is recording. However, you can only watch the standard VHF channels.

What about programmable VCR's? The problem associated with programmable VCR's is common to both the converter box and the decoder. The programmable VCR must have all of the channels available to it on their own separate frequencies for the programmable feature to function properly. If those channels go through any type of converter device (like those that were described earlier), then the VCR's tuner must remain tuned to the output channel of the converter device. None of the installations outlined so far are compatable--to a- j:irogra-mmab1e"VCit There are several methods to get around the problem but the simplest and most effective is by using a VHF-to-UHF converter. What is a VHF-to-UHF converter? Thi s converter does exactly what the name implies: it converts the entire VHF band up to the UHF band . It is a simple device that replaces most of the components that have been necessa ry in the first three figures . Figure 4 shows a VHF-to-UHF converter in use with a programmable VCR . The cable signal feeds into the VHF input of the device: that is all 30 or more channels carried at VHF frequencies on the cable system. The device passes the basic 12 VHF channels, (2 through 13) straight through and on out the VHF output terminal of the device. Now available at the UHF output terminal are all of the 30 VHF input channels <including Channels 2 through 13), now at UHF frequencies.


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FIG. 4-A VHF-TC-UHF CONVERTER enables you to watch all the cab le channels while the VCR Is recording a different channel. That connect io n provides the Ideal solution.

There is no longer any need for the cabl e TV converter box as that device mak es all of the cable chann els ava ilable to the VCR thr ough the VHF/ UHF terminals and now the VCR ca n pass those chann els on to the receiver in the sa me mann er. The end result is that now e veryth ing works j ust as it would on your own house antenna or any othe r 12-ch annel syste m. The programm abl e VCR now has all channels available at frequencies that will enable the program mable feature to wor k normally. Yo u will need the con version ch art for those additional cable channels that are now ava ilable on the UHF tuner. it will tell you that cabl e Channel A is now UHF Channel 47. and so on. (See Tabl e I.) The VCR/TV switch on the front panel of the VCR will now function as it was orig inally intended. If you had a built -in remote-control de vice with your TV that had been rendered useless for cha nnel selection since the cable con ve rter box was installed you can dust it off and start using it again also). One sourc e for the VHF -to-UHF conve rt er is ETCO Electronics. North

Cable TV plus off-air pay-TV Chances are that if you have a cab le sys te m plus a local pay-TV channe l availab le, the cab le sys tem will already carry that pay-TV cha nnel and make it availab le to you through a normal con ve rte r de vice that would be co mpatable with the sys te ms show n ea rlier or th rou gh a UHF-to-V HF convert er, A ca ble system decode r wou ld also be t reat ed in the same manne r as the con ve rte r box. In the case where the cab le system does not carry the local pay-TV channel, a nd it is only ava ilable through off-air recep tion and you still want to have the cab le syste m plus the pay-TV chan nel, you are going to have to use a little of eac h of the syste ms that have been discu ssed so far. (You are also going to be paying a pretty high monthly T V bill.) Bec ause of all the various possibilities in different areas of the co untry and the va rious methods emp loyed, Fig. 5 shows a typical solut.on to that kind of prob lem and you ca n modify or build on to suit the requirement s of your pa rticular needs . In F ig. 5 both pay-TV and cable are kept separate thro ugh the entire insta llat ion. Th at prevent s any adjacent probl e ms or othe r problems due to lack of available unused channels to acc ommod ate the preselected output channels of the various devices (VCR, decoder, UH F co nve rter). Th at type of inst allat ion also eliminates the need for a ny type of manual switching netwo rk, another pote ntial source of mixing problem s. PAY·TVIN


TABLE l-WHERE THE CABLE-TV channels are moved to in the UHF band when using a UHF-to-VHF converter










6 o« a: 54



2 =36 3 =37 4 =38 5 =40 6 =41

7 =56 8=57 9=58 10 =59 11=60 12=61 13=62

A =47 8 =48 C =49 0 =50 E =51 F = 52 G =53 H =54 1=55

J =63 K =64 L =65 M =66 N=67 0 =68 P=69 0 =70 R=71

FIG. 5-PAY-TV can be added to a cable-TV in stall ation along with a VCR as s hown above. A ll the feat ures of a prog ramm able VCR are retained.

The pay -TV signal is processed thro ugh the decoder and then fed into the VHF input terminals of the VCR. Most off-the-air decoders have two input s. one for your house sys tem and the other for the off-the -air pay-TV cha nne l. The re is a front pane l switch that allows you to selec t either the regular house syste m or the decoded pay-TV cha nnel that will be on a pre-

se lected output channel (i.e., Channel 3). In the insta llation shown in Fig. 5 you wo uld simply leave the decoder sw itc hed to the descramble (premium) position and then wheneve r the pay-TV channel is broadcas ting it would be avai lable to your VCR or TV , decoded on Channel 3 (the preselected output cha nnel of the device) . That would also be the onl y channel on the VHF tune r of both the VCR and the TV . On th e cable side, all of the ava ilable ca ble cha nnels would be up-con verted through the VHF-to-UHF converter and wo uld now be ava ilable on the UH F tu ners of both the VCR and the TV . (See Table I for a channel conve rsio n ch art.) Th ere is one additional modification to th is type of installation that might be nec essary if your home video sys tem is readily accessible to your friends and neighbor s. Anyone who is not familiar with that type of installation will have problems operating the TV set. When the y switch the tuner over to a ny conventional VHF channel on the set itself they will find eve ryth ing is snow ex cep t for the single pay-TV cha nnel. All of the remaining channels have been up-converted and are now available only on the UHF tuner. If you feel that it is necessary to have the regular VHF channel s bac k down on th e VH F tun er you can do that with j ust a few modifications to the installation show n in Fig . 5. Start by insertin g a two-way coax signa l splitte r on the input side of the VHF-to-UHF converter. Leave one leg still attached to the VHF input of the VH F to UHF con verter and run the oth er leg to the input of the decoder device that is norm ally intended for your hou se antenna. It will be necessa ry to move the decoder device to a physically co nvenient spot near the TV or VCR as you will now have to switch the outp ut of the device back and forth manu ally from either the pay-TV channel or the VHF Channels 2 through 13. Now you' re able to leave the sys tem with the co nve ntional VHF Channels 2 thr ough 13 avai lable on the TV for anyone who wa nts to watch TV or you can switc h bac k to the setup in Fig. 5 that enables your programmable VCR to select anything (cable or pay-TV) availa ble for recordin g. Helpful hints Kee p it simple. The fewer active dev ices or switc hes, the more reliable and troubl e-free your syste m will be. If you have two or more pay-TV channels available in your area, or you want to run the output of your VCR to several different rooms in your home (or maybe you have two or more VCR' s, or maybe you have all of those), your best bet is to use a centrally located co n tinue d O il pa ge' 104

LlNICDflN-1 fleBey Part II-By the end of this section, your r ob o t's arm will be operational. Here are instructions for completing the arm, and for building several types of hands.



build for between two- a nd-four hu ndred dollar s, dependin g on your ingenuity and scrounging abilities. It is fully mobile and has th e ability to use its arms and hands. It can be contro lled by a cable link to a console, by radio control from a console, or in conjunction with a computer. Th e first part of this series describ ed some of the components used in the robot's const ruc tion, and covered most of the asse m bly of it s ma nipulat or(s) (ar ms) . In this insta llment we will complete Unicorn-One's manip ulators and build its end-effectors (hands) . From time to time we will present you with certain options that you may or may not want to include in your version of th e rob ot. Remember that one of thi s project' s objec tives is to build a workin g robot, but at a reasonable cost. When you start adding frills-which you may consider necessities- that cost is goi ng to go up. It might be wisest to sta rt with t he essentials, to prove that what you have set out to do can be done, and to add the extras later. Unicorn-One was designed with that plan in mind and all th e options describ ed- as well as most extras that you' ll think of yourself---ea n be added afterward, with no major alte rations to the robot alrea dy const ru cted . Completion of manipulator The last part of the manipul ator to be fabricat ed is th e contractor-bar (we saved the easiest for last). That is simply a bar of alumi num 'f. X ' f, X approxi mately 6

inches long. The act ual length will depend on how far you want the elbow to bend, but we've found that 6 inches is a good size to work with. Use a No . 33 bit to drill a hole close to each end of t he rod so it may be connected to the rest of the arm with No. 4-40 screws at the two contractor-bar pivot pieces. See Fig. 9 and Fig. 6 (part I, last month) for detai ls. At this point you are probably anxious to see how (and whet her) the elbow acti on of the manipulator works. Before

FIG. 9-MANIPULATOR. showing con tractorba r and its aU achment to the two pi votpieces.

you power it up, th ough, th ere is one more step that must be taken. If you were to turn on t he mechan ism now there is a very good cha nce that you would unintentionally allow the t hreaded rod to travel too far . . . and jam. T hat could prove extreme ly embarr assing . To prevent jamming from taking place, we have to install limit switches. Those are lever-ty pe snap -actio n switches that are placed so that power to the elbow

motor will be cut when the part in motio n reaches the desire d limit of its travel. Both upper- and lower-limit switches are used to protect the mechanism dur ing motion in either direction. If power is applied to the elbow motor through one of the limit switches, the threa ded rod will turn and cause the forearm to move up or down. When it has gone as far as it can, it will contact t he limit switc h and stop the motor. Since we are using DC motors, reversing t he current flow in the windings (connecting t he power source "b ackward s" ) will make them turn in the opposite direction. Therefo re, to make the ar m move the other way, the other limit switch supplies the motor with cur rent of th e opposite polarity. Almost any size lever-type, N .C. (No rmalty-Closed) snap-act ion switch may be used, as long as the re is room to mount it. There is no firm ru le as to where the limit switches must be located-the object ive is to place them so that t hey will be turned on by some moving part of t he arm in time to stop its motion before damage occurs . Figure 10 shows one possibility for th e placement of the upper- and lower-limit switches . Here, the upper- limit switch is attached to the side rod so that its contacts are opened when it is contacted by the upper pivot hinge. The lower is placed so it will contact the side rod when t he arm is lowered and th e side rod and contactor-bar are nearl y parallel. Th ere are other ways of achieving the same results, of course .



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There are two things to bear in mind when placing the limit switches . First, make sure that positive contact will always be made and that there is no possibility that the switch can be turned on accidentally. Second, when taping the switches' wires (and those of the other electrical parts, such as the motors) in place, take care that the tape and wires do not impede the action of any of the moving parts . T he wiring of the limit switches, endeffectors and motors will be covered in some more detail toward the end of this section. End-effectors An arm is of little use without a hand at the end of it, so we will present two elementary, but serviceable, types of endeffectors for you to choose from and give you the option of constructing a more comp lex (and expensive) one, should you so desire. The two basic hand types we'll describe are the finger and the claw. Your robot, being ambidextrous, can actually have one of each, using one for one purpose, and one for another. The grasping action of both types of hand is provided by solenoids-i-electromagnetic coils with rods through their centers . When . a current is passed through the coils, the rod is either pulled into them or pushed out of them. If that rod is connected to part of the hand, the hand will close (in our case) when power is applied to the solenoid. When power is cut, the hand opens by means of a spring which is either part of the solenoid or part of the hand mechanism itself. Selection of the solenoids is not critical. T here are three conditions which must be satisfied: voltage, size, and degree of travel. The solenoids should be rated to turn on with 12 volts since the robot will almost certainly be using a self-contained 12-volt storage battery when it is operating under its own power. The size of the solenoids will determine the strength of its grip. You may want to use a stronger solenoid in one hand than in the other to allow the robot to perform tasks requiring




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FIG. 11-FINGER-TYPE end-effector assembly drawing. Hinge construction is described in text.

different degrees of delicacy. As for the degree of travel (the distance of the solenoid's rod can move) we've found that a 'h - to-vs-inch rod allows the hand to open far enough for most app lications. Finger-type Dimensions of the finger-type endeffector are shown in Fig. 11 and one of the completed units in Fig. 12. The mate rial used for that part is '/,6 X '/,-inch sheet aluminum. The fixed (upper) finger is made from a piece 3.3 inches long and the movable (lower) finger, from a 3-inch one. The angles shou ld be formed by placing the meta l in a vise and bending as evenly as possible . Use a hammer to give uniformity to the surface. The finger contractor-bar is made of '/, 6 X 'I.-inch aluminum, drilled at both ends . The length depends on the solenoid's travel. As shown in Fig. 11, a halftwist is put into that bar. One end of the bar is attached to the solenoid, which is mounted on the outside of the fixed finger, and the other is inserted through a slot sawed in the outside edge of the movable finger and secured with a cotter pin or similar device. The movable finger is attached to the hinge (refer to Fig. 13) by two No. 4-40 screws . The hinge itself is supported at

FIG. 12-COMPLETED FINGER-TYPE end-effector. Gear is non-functional, but adds to appearance.

one end by a 'f,-inch diameter piece made from a section of an aluminum stand-off wit h a long No. 4-40 screw acting as the hinge pin. The finger jhinge assem bly is FIXED CLAW


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FIG. 13-DETAI L S OF HINGE use d in fingertype end-effector assembly .


fastened to an end-plate one inch or more in diameter and If, inch thick using No . 8-32 screws and that, in turn, is mounted to t he last cross-rod of the manipulator's forearm . The original Un icorn-One used a non-functio nal gear to build up the end plate and to give the robot a touch of class. The finished end-effector may be fixed horizontally, vert ically, or at any angle in between . Its position depends on the use to which the member will be put. Claw-type For heavier-duty applications, you might want to use a claw-type end-effector; that type of hand is shown in Figs. 14 and 15. On 'I.-inch aluminum plate, use a scr ibe to mark the outline of the two sections . Rough-cut the pieces, taking care to keep to the outside of the outline to allow a margin for error. Using a hacksaw on the inside angles of t he claw may prove to be difficult or even




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' USEONE CENTER, ORTWO SIDE, MOUNTINGHOLES AS NEEDED FIG. 14- CLAW-TYPE end -effector assembly d rawing. This is a heavier-d uty me c hanism than the finger-type and yo u may wa nt one of each .

impossib le. Instead, try drilling a closelyspaced series of small holes along the outside of the part. Then, using a cold chisel, knock it out and file it to shape, along with the rest of the claw.

Drill two small holes th rough the two claw sections, in the plane of movement (parallel to the flat sides of the claws), to pass the cable from the solenoid, which can be anchored by a screw to the lower

PARTS LIST Item Sheet aluminum Sheet aluminum Sheet aluminum Solenoldt Solenoidt Solenoidt Solenoidt Solenoidt Snap-action switch Snap-action switch Machine screws Machine screws


Supplier's part no.


.0625 in. thick

1 X 7.5in.'



.250 In. thick

1.5 X 6 in.'



.250 in. thick

0.5 X 6in.



Size 50, 'h X 1in. 12 VOC Size 75, 'I. X 1'hin. 12 VOC 'h-In.stroke, 12 VOC 'h-in.stroke, 12VOC "0"- frame, 12 VOC Subminiature roller- Ievertype,5-amp Subminiature lever- type, 5-amp 2-56 X 'I,














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SUPPLIERS A The Robot Mart Room 1113 19 W. 34th St. New York, NY 10001 (Catalog $3.00) B Winlred M. Berg, Inc. 499 Ocean Avenue E. Rockaway, NY 11518 F Ledex, Inc. Box 427 Vandalia, OH 45377


G~ard ian

Electric MIg. Co . Advertising Dept. 1550 W. Carroll Ave. Chicago, IL 60607 r(Write for list of local ,~ distributors.) >

H Liberty Controls, Inc. .~ 500 Brookforest Avenue ,'t, Shorewood , IL 60431 I Radio Shack Consult your local telephone direct ory .

NOTES: Items marked with " ." were atready specified in the parts list for Part One of this series. Items marked with " t" are to be select ed according to the builder's requirements. Components may also be available from suppliers other than those indicated. Some suppliers have minimum order requ irements. Inquire before ptacing order.



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FIG. 15-ASSEMBLED CLA W-TYPE end-eff ector. Piano wire may be used to connect solenoid and lower portion of claw.

claw. A small hole should also be drilled into the jiat side of each claw into which the ends of the spr ing which will keep the hand open when the solenoid is not tu rned on. Robot manipulator -claw springs are not an off-t he-shelf item in most places, so you' ll probably have to make your own. Figure 16 will give you an .idea of what you' ll need. If you haven't taken apart any clocks recently, you might tr y using a section of the type of spring used to close

FIG. 17-ROTATABLE end-effector mentioned in text. Stepper motor supplies wrist act ion .


HAND+12V (Ll)








BLUE FIG. 18-WIRING DIAGRAM for manipulator and end-effector. Color-code wire s in order to avo id confusion.

FIG. 16-CLAW-TYPE end-effector showing homemade torsion spring. Text gives details.





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screen doors in the summer. Mat erial v»in. in diameter seems to work out well. The tension of the spring will affect the claw's actions. If it's too strong, the claw will not close properly and the robot' s grip will suffer, and if it's too weak, there can be problems with keeping it open. If that sounds confusing, bear in mind that the pur pose of this particular spring is to hold the claw open, not closed. Attachment to the manipul ator is similar to that for the finger-type end-effector, but you may decide to mount the solenoid (which will probably be larger than the one used for the other) directly on the forea rm and feed th e cable th rough to the claw. You might want to line this hand-or possibly both- with foam rub ber or a similar material to give it a better grasp on slippe ry objects. A more elaborate type of end-effector is shown in Fig. 17. It also uses the clawtype mechanism but has an additional degree of f reedom-a te rm referr ing to the different ways a joint can move. (Yo ur own arm, for example, has three degrees' of freedom: It can twist, move up and down, and move from side-to -side.)

Th e added mobility is gained by placing a stepper motor between the ar m and the hand. Th e ste pper motor 's shaft turn s through a small porti on of an arc each time a short elect rical pulse is applied to it. The result, if enough pulses ar e applied, is a twist of the wrist-and an added degr ee of freedom! Because those pulses are best genera ted by a digital electronic circuit-which we have not yet discussed- we'll postpone a description of the construction of this type of hand until we start puttin g toget her Unicorn-One's electronics. For certai n applications, tho ugh, it can be indispe nsible. Wiring and testing A wiring diagram for the motor, solenoids, and microswitches, with the ir associated controls, is shown in Fig. 18. The eight-position terminal strip illust rate d is actually part of a 32-position strip, which will terminate all motor and switch connections . Since 32-position terminal blocks are difficult to locate, do the best you can with smaller ones-but allow for at least 32 positions. That will give you several extra positions which you can later use for your own options. Color-code the wiring to simp lify circuit tracing and make sure that everything goes to the right place and that you

have electr ical contin uity . Now , with the limit switches installed, you can check out the actual operation of the manipulators and end-effectors. In fact, this is the best time to do so. (If you were to wait any longer , and the ar m were attac hed to the body, you might have to do quite a bit of teari ng-apart to get to, and correct, any problem that showed up.) The parts list shows sources of supply used by the aut hor. There are certain to be others, though, possibly more accessible to you. In fact, many of the materials specified can probably be found, in a form close enough to work with, at your local hard ware or buildin g-suppli es store. Even closer-arid more economicalmay be your basement or a nearb y junkyard. The next part of the Unicorn -One series will concern itself with design considerations and construction of the robot's mobility base-the section that gets it from place to place. Also included will be details of the main 32-position term inal strip, which will be the heart of the robot's electrica l distributi on and control system. The design of that section will permit easy changeover, when you're ready, from manual control by cable-connected console to radio control and, later, to cont rol by microcomputer . R-E

PIEZOAPPLICATION S ELECTRIC SOUNDER Solid-state " beepers" have a variety of interesting applications. This should give you a few ideas. CALVIN R. GRAF, W5LFM

radio-frequency interference (RFI) th at can be detected beyond 10,000 MH z. Th e breaker-point lever is connected to a metal disc that vibrates the air to produce a sound. This type emits a buzzing sound and has a high harmonic content that is usuall y harsh sounding. Oth er s of this type use a small motor to vibrate against a metal or plastic disc to produce a sound.


a re good questions to ask, bec ause the piezoele ctric sounder is partly both but unique in its own right. It doesn' t bu zz , so it's not a buz zer. It doesn 't click like the telegraph sounder of days past , so it' s not a clicker. But it does sou nd out wit h a pure tone whe n a DC voltage is applied to it, and it oper ate s on the piezoelectric effect. So it is accurately called a piezoelectri c sounde r. First introdu ced by P. R. Mallory abo ut 15 years ago, t he sou nder was called the Sonalert . It immediately found wide acceptance by the electronic ci rcuit-a nd-sys tem designer bec ause it emit s a near spectrallypu re 2900-Hz ton e when a DC voltage between I and 28 volts is applied to its terminals. The piezoelectric sounder has been used extensive ly in applica tions where a low-current annunciator is needed. Those include wrist watches, alarm clocks, radio beepers, telephone sets, smoke detectors, testing devices, electronic games, intrusion alar ms, auto mobile warning and monitoring, office mach ines, electronic calcul ators, timers, and comput er per ipherals. Many manufacturers pro duce piezoelectric sounders tod ay. A typical unit is shown in Fig. I. A Sound Approach So und wave s, as you know, are va riations in the rate of change in the so und-press ure level. A frequency , or tone , is a measure of the air-press ure variation. A foghorn prod uces slow va riations in air pressure. The whine of a jet engine is produ ced by many va riations in air pre ssure. A ride in a fas t elevator or a passing weather fro nt are also examples of air-pressure

FIG. 1-THE PIEZOELECTRIC SOUNDER is a low-current device that produces an almost pure tone. This is a Sona/ert, made by the Mallory Components Group of Emhart Corp.

chan ges. Howeve r, those are not rapid enough for us to hear as sounds, but we do feel the effect on our ears or see th e effect on a barometer. What freq uencies are most pleasing to the ear? Research has shown that so und- pressure changes between 700 and 900 Hz are most pleasing to the ear. Those frequencies which att ract our atte ntion the most lie between 2000 and 4000 Hz. And you probably we ll know that a pulsing so und will rea lly get our attention, as co mpared to a continuous tone . Ways to sound off In the army , everyone learns to "sound off' by counting " one, two, three, four. " In electro nics there are c urrently three way s to produce an alerting sound. Electro mechanical-The familia r buzze r is probably over 100 years old. Th at type of audio prod ucer consists of a mechanically-tuned lever with con tac ts that ' vibrate back and forth much like a relay using breakerpoint switchi ng. The making and breaking of the current, however, generates

Speaker-Oscillator-This type of sound producer is a speaker (usually ve ry small and compact) used to deliver sound gene rated by an electronic osc illator circuit. Piezoelectric Transducer or SounderTrul y solid state, this type uses a thin ceramic element bound to a brass disc. The element is connected to a builtin osc illator that drives the ceramic ca using it to vibrate a brass disc which flexes and generates a sound wave. This type of sounder is a low-power device that produces a high audio output, and has a long ope rational life. The piezoceramic sounder by itself (without its transistor driving oscillator circuit) transforms AC voltages to sound-pressure waves. It will also generate an AC voltage across its terminals when stimulated, or vibrated, by a sound-pressure wave . (Is it a spea ker or is it a microphone?) Basic circuits and uses Th e bas ic circuit for the piezoelectric sounder is shown in Fig. 3. It can be used in circuits built around TTL, CM OS, 9-volt transistor batteries, and 12-volt automobile batt eries. The so und-o utput level increase s directly with applied voltage, sta rting near I volt and increasing to 20 volts. A higher vo ltage, approaching 30 VDC, can be used if applied for short periods of





m ~



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time (a few seco nds). The piezoelectric sounder is readily available from man y part s sources and its characteristics are show n in Table I. In Fig. 3. we show a new symbol for the piezoelectric sounder using two wavy lines to indic at e that it generates aco ustic energy. A single wavy line (sine wave cycle) indic ates a gene rato r but without further de signation as to whether it is a powe r generator, an audio gene rator, or a signa l (RF) gene rato r.




FIG. 4- The PIEZOELECTRIC SOUNDER is made to pulse at a 3 pulse-per-second rate by adding a flasher LED.

Table 2-S0UNDER AND FLASH RATE vs. voltage and capacitance (refer to Fig. 5)

Table 1-PIEZOELECTRIC SOUNDER CHARACTERISTICS Typical Solid-state Piezoelectric buzzer

Capacitance, C




.4.8 kHz 1.5 to 20 VDC 9 mA at 9 VDC 1 3/8 " by 3/8 " th ick

Flash/ Sound Rate


6 puls es in 5 seconds 4 pulses in 5 seconds No output



4 PPS 2 PPS No output

100 /IF


4 PPS (soft not e) 2 PPS No output

6 VDC Frequency Voltage Current Size



the pho tocell is illuminated (low photocell resistance), but will remain on continuously in the dark (high photoce ll resis ta nce) . In Fig. 7, we see a circuit ar ra ngement that draws no current in its standby, or dark mode (high photocell res istance), but begins pulsing when the light level reac hes a certain level (low photoce ll res istance) . The circuit gets its power from a 9-volt batt er y. We will now look at a very simple circuit that uses the low-current cha racteristics of the piezoelectric sounder. With it, we can check for continuity, or for vo ltage in a circuit. The few components required for this simple tester can be ass embled in the plastictop cap of a shave cream or oth er spray can . Use two 24-inch long leads with alligator clips for test leads. Continuity Tester-The circuit in Fig . 8 is arra nged so when the switch is set for CON TINU ITY , a small amount of curre nt is drawn through the piezoelectric sounder and the external circuit und e r test. By shorting the probes, you ca n establish an audio refere nce 4.7K

FIG. 2-THIS SOLlD·STATE BUZZER operates with 1.5 to 20 volts DC and delivers a 4.8-kHz signal.

Flashing and sounding circu its By adding a flasher LED and seriesdropping resistor as in Fig. 4, we are able to make the piezoelectric sounder pul se or beep, at the flash rate of the flasher LED. (Be careful and do not confuse the flasher LED with Nation al' s LM3909 LED flasher/oscillator. ) The 1000-ohm resistor limits the voltage applied to the flasher LED (nom inally 5 VDC) . In the circuit of Fig . 4, the pulse rate of the sounder is 3 PPS . Th e pulsating sounder can be used in automobile tum signals and electronic a nd electrica l troubl e-shoot ing. When mounted on the rear of a vehicle and powered from the back-up light circ uit it becomes an automotive backup wa rning device. The flasher LED is readily available from several manufactur ers. Th e flasher is an IC that switches 1TO 20·V OC


voltage to a LED at a 3 PPS rate . Current drawn at 5 VDC is about 20 mA o The cos t is under $2. We vary the pulse of the piezoelectric sounder by connecting a capacitor across it as in Fig. 5. Now the flasherLED flash rate is sensitive to applied voltage as shown in Table 2. Light Input to Photocell-When we place a photocell across the piezoelectric sounder , we make the circuit sensitive to ambient light. Figure 6 shows a circuit that will make the sounde r and LED pulse at 3 PPS when


Z o a:


frl..J W




+ '"




FIG. 3-BASIC CIRCUIT AND SYMBOL fat the piezoelectric Sounder . Sound {,"ergy Is pro duced with as little as 1 rnA.


+ + -I

9V :


FIG. S-VARYING PULSE RATES are produced by plac ing a capacitor across the sounder. (See Tab le 2.)


~ ~



FIG. 7-CONNECT A PHOTOCELL in series to turn the circuit off in the dark (high photocell resistance). Light will cause the sounder to pulse.



FIG. B-CONTINUITYIVOLTAGE TESTER using the piezoelectric sounder. Observe correct pola rity fo r voltage tests .

level for zero ohms. An open circ uit is ob viou sly infinity and no sound is produced. With a good ear and a good batter y, you will be able to hear an indicat ion for 20K to 30K resistance in the circuit unde r test. That arrangement is good for testing continuity of light bulbs, resis tors, diod es, coils, tran sistor s, motors, relays, etc. When you test volume cont rols for continuity, you can spot a " scratch y" contro l because the audio level of the tone of the piezoe lectric sounder will shift abruptly. continued on page 99

Better than DOLBY B111 New Noise Reduction System for Tape Recorders ' LEN FELDMAN CONTR IBUTING HI-FI EDITOR


a debt of gratitude to Dr. Ray Dolby. His introduction of the Dolby B noisereduction system more than ten years ago was largely responsible for the wide acceptance of cassette tape recording as a true high-fidelity program storage medium. Although the cassette format delivers much higher performance quality today than it did ten year s ago, it is still far from being a "noise-free" system. The Dolby B noise-reduction system represents a clever choice of compromises that provide a reasonable amount of noise reduct ion with a minimum of undesirable side effects, at low cost. Those compromises involve limiting the total amount of noise reduct ion as well as the frequency bandwidth of the system. Until now, the tape-record ing enthusiast has had to be content with the 8-to-IO dB of signal-to-noise improvement of the Dolby B system. While modem cassette decks almost universally have built-in Dolby B, tremendous strides in the quality of pre-recorded program sources and a growing interest in live recording demand further improvements in cassette deck performance. Critical listeners often feel that the Dolby system does not provide enough noise reduction for those more esoteric recording application s. Pri nciples of noise reduct ion Nakamichi first became interested in developing a better noise-reduction system several years ago, after evaluating a profe ssional noise-reduction system called Telcom C4D developed by Telefunken of Germany. According to Nakamichi, that system (although

This new noise-reduction system from Nakamichi provides

a dynamic range 18 dB greater than Dolby B. too expens ive for consumer application s) provided an unusually large ratio of noise reduction and was particularl y free of such undesirable side effects as noise pumping or signal coloration . A cooperative effort between Telefunken and Nakamichi has resulted in a modified consumer version of that noise-reduction system , Nakamichi calls it High-C om II. Nakamichi's first commercial version of the system is in the form of a separate add-on device, (see Fig. l) that can be added to any high-qualit y cassette deck .


- ---- "






_;.--.:.-_= .. ,


-=.. ;; -

Fig . 1-HIGH-COM II noise-reduction system can be used with any hlg h-q uality cassette deck.

Before discussing the specifics of the High-Com II noise-reduction system, let us examine the basic principle behind noise-reduction systems. The compander concept that forms the basis of all noise-reduction systems is quite simple. Before recording, the dynamic range of the program is compres sed by a circuit, the signal of which is controlled by the signal level itself. Once compressed, the program " fits" on the tape. The weakest signals are amplified and recorded at a level well abov e the tape noise while strongest signals are comp ressed and recorded below the level at which distortion occurs because of tape saturation. During playback, the exact converse action takes place: Strong signals are expanded or amplified to compensate for the compression they receive during recording, while the level of weak

signals is reduced, restoring them to the relative intensity they had before recording. While the basic principle sounds simple, Nakamichi soon discovered that designing a cost-effective noisereduction system that works well in conjunction with a cassette deck is not an eas y task. Each element of the system had to be carefully considered and optimized. If nece ssary , a compromise between optimum and practical had to be selected. The ultimate choice of the compression/expansion ratio is a good example. For an expander to be free of noise pumping, most of the recorded signal must be well above the noise floor of the tape . Since the cassette deck' s low speed limits the maximum signal levels that can be recorded on the tape, a relatively high compression ratio is needed to maintain a great enough margin between low-level signals and noise . If too high a compre ssion ratio is cho sen , however , it becomes difficult to recover the original dynamics dur ing expansion and the entire system becomes very sensitive to slight level variations, such as those caused by incon sistencies in the tape coating itself. New noise reduction system In the High-Com II system, a 2: 1 compression ratio is used to get a 20dB impro vement in signal-to-noise. The 2: I ratio is maintained throughout most of the dynamic range of the systern, exce pt at very low input levels, where the ratio is restored to I: I. That largely linear-transfer charac teristic of the syste m makes it relative ly immune to minor mismatches in level. The 2; I







ratio is not enough, however, to overcome noise pumping completely. That effect is caused by a compander at frequencies other than those of the input signal. A good example of that is recording a single tone. Noise in the immediate vicinity of the tone's frequency will be masked by the tone signal itse lf; but noise well above or below that frequency is not masked. It is the modulation of that unmasked noise by the ac tio n of the compander that is often not iceable and objectionable. What makes matters even worse is that with 20 dB of basic noise reduction there is less of a constant overall hiss level to mask the noise modu lation , Both th e professional Dolby-A and Telcom C4D noise -reduction systems effective ly eliminate that type of noise modu lation by processing the signal in four fre quency bands. In other words, compand ing action in one frequency range is co ntrolled separately from that in another. Such a complex configuration is fa r too costly for a consumer ve rsion of either system. The Dolby B sys te m combats the problem by limiting its operation to only the high frequ encies. The action of Dolby B can be und erst ood by referring to Fig. 2, a seq uential trace of residual tape noise, using a spectrum analyzer over the ra nge from 20 Hz to 20 kHz. Vertical

tem deals with that problem and minimizes noise pumping still farther by processing the signal in two bands . Using more than two frequency bands would, of course , provide added insurance against noise pumping , but the benefits had to be weighed against the cost. The Telefunken HighCom IC, developed for the High Com II, provides a wide selection of attack and release times, and with two bands of processing, an appropriate set of dynamic characteristics could be selected for each frequency range . Comparing the noise-reduction results obtained by using Dolby B (Fig. 2) with those obtained by using the High Com II system (Fig. 3), both the increased amount of noise reduction and the fact that some noise reduction is taking place even at mid-to-Iow frequencies are obvious.



0 1--+--+-----1-



+-+ -+--;)(1:/'1---;



-1 0 1--t--+-+--+~lj9'.fI-t--+---;


~ - 20 f-+-"'-I-~"'/r-.,,j£--II--t--+---t


Fig. 2-HOW DOLBY B compensates for highfrequency noise. Act io n beg ins above 1kHz.


a Z occ IaLJ.J ...J



o« cc


+20 +1 0

-10 -20 ~

.!J w > w

- 30 --40

-' - 50 - 60


- 80 - 90

Fig . 3-EFFECT OF High-Com II on res idual tape noise. Compare th is with Dolby B in Fig. 2.

se nsitivity is 10 dB per box . Note that the two plots (without and with Dolby B tu rned on) are identica l from around 20 Hz to just beyond I kHz . At that point the action of the Dolby B system red uces high-frequency noise at a sliding or increasing rate (lower noise trace) out to the limits of the sweep. T hat makes sense for cassette tape beca use the overwhelming proportion of noise at the slow tape speed is highfrequency hiss. However, with 20 dB of noise reduc tio n provided by the High-Com II system , it is no longe r acceptable to concentrate so lely on the higher freq uencies. A 20-dB reduction of hiss with no corresponding red uction at low freque ncies would only make low-frequency noise equally more audible. The High-Com II noise-reduction sys-

Figure 5 shows the record-play amplitude response and noise analysis of the High Com II system coupled to a Nakamichi Model 680 cassette deck using metal particle cassette tape. It was supplied to us by Nakamichi. The pen traces on the lower right comer of the figure show wideband noise levels


+10 +20

Fig . 4-ENCODING/DECODING and input/ output characteristics of the High -Com II system.

Figure 4 shows the encode and decode characteristics of the High Com / / system and its input/output characteristics. The 0 dB shown is the reference level of the system and the level recorded on the tape for that reference is 200 nWb/m (Nano-Webers Metermeasure of magnetic flux-dens ity). The degree of encoding or decoding is small at low frequencies , increasing as the frequencies get higher. Depending upon frequency , below a certain level the encode-to-decode ratio becomes I: I, suppressing the breathing noise changes in signal levels cause .

with various weighting filters . Note that the noise reduction with no weighting filter applied is a full 19 dB. With .. A" weighting, the noise reduction is exactly 20 dB, or about 12dB greater than with the Dolby B system. Actually the increase in dynamic range is somewhat better than 20 dB because, unlike the Dolby B system, the Hig h Com II system continues its companding action beyond the reference 0 dB level. Since 3% total harmonic distortion on that tape deck normally occurs at a true recording level of +6 dB (0 dB equals 200 nWb/m), the 2:I compression level permits an input level of + 12 dB as a maximum. That accounts for the high output of the + 10dB trace in Fig. 5. It would normally be lower because of saturation, but with the 2: I compression, the actual record level reach ing the tape is equivalent to +5 dB. Since the" A" weighted noise with the High Com II system turned on is 74 dB below 0 dB, the total dynamic range available, referenced to the 3% total harmonic distortion point, is 74 dB plus 12 dB or 86 dB ! That is a full 18 dB better than the dynamic range that is available (referenced to 3% total harmonic distortion level) using Dolby noise reduction. To preserve high-frequency transients, any compander must have a fast attack time. It must recognize an abrupt change in signal level quickly, or the characteristics of the transient will be altered or destroyed. On the other hand, if the compander has too fast an attack time , it will tend to folcontinued on pag e 104



operate at a single, standar d speed of 1'1. inches -per-second. All, that is, except B.LC./ Avnet Corporation's new series of ste reo casset te decks, each of which opera tes at that speed and also at twice that speed, or 3'1. ips. Three such two-speed decks are now being marketed by B.LC./ Avnet, and, in all likelihood, even more models (proba bly higher pr iced than the first mode ls) are on the way. T here are many indu stry rumors about how B.LC ./ Avnet was able to " break with trad ition" (not to mention the Philips agre ement t hat presum ably governs all cassette-deck manu factu rers, since Philips originated the cassette -tape format) , and offer speed options in cassette decks. In any case, B.LC ./ Avnet has done it and assures everyone that the company is on safe legal ground. We certai nly hope so because with increased speed comes vastly increased performance capability. Of the three two-speed decks now available, we chose to test the third-the top-of-the-line model T-3, which is the first of those decks to offer true th ree-head operat ion and its related tape-monitor ing capability. In the mode l T-3, the record and play heads are elect rically separate component s, but are mount ed in a common housing. As a result , no tape azimuth alignment is required, as would be the case when thr ee-head decks use physically separate d record and play heads. A front-panel view of the model T-3 is shown in Fig. I . Th e left -hand section of the black front panel contains the cassette compart ment; when the STOP/EJECT push-butto n is depr essed, th e cassette door opens smooth ly and slowly (the action is viscous-damped). Additional piano-key-type tape-tr ansport controls below the cassette compart ment includ e a RECOR D switch; REWIND. PLAY, and FAST-FORWAR D switches; and a PAUSE switch. Tape motion is contro lled by a dual-capstan tapedrive system powered by a two-speed DC servomotor. Th e POWER on/off push-button is

located in the lower left-hand corn er. To the right of the cassette compartment are a th ree-digit resettable tape counter, a MEMO RY push-bu tton (that permits you to rewind th e tape to a preset zero point on the digit counter) , and a pair of calibrated peak-reading record-l evel meter s that can be accurately read all the way from -40 dB to + 5 dB. Note that "0 dB" on those record-level meters corresponds to a level of 200 nanowebers-per-meter (rat her than the lower 185 or 160 nW-permeter ofte n used as 0 calibration points for cassette-deck meters). Keep that in mind when evaluat ing the headroom figures cited later in this art icle. An innovatively designed LED indicator is located between the two peak-reading meters. As long as peak record levels are in a safe (or low-distortion) area, the LED glows green . If instantaneous record levels exceed the value considere d acceptable by B.LC./ Avnet, the LE D magically changes color and glows red, warning the user to back off on record levels or suffer the consequences of over-recording and high distorti on levels during playback. Below the two meter s are a pair of large, concentrically-mounted record-level contr ols, while to the right are an output-level control and a separate phone output-level control. Th e deck can therefore handle headphones with a wide range of sensitivities, and you can adjust the sound level from the headphones without affecting main outp ut level that is being fed to the rest of the system . The lower edge of the front panel contains a speed-selector switch (with settings for 1'/ . or 3'1. ips) ; and an equalization-selector switch (with settings for either 120 or 70 us). There is a three-position bias-selector switch (marked low, nor mal, or high, rather than being referenced to specific tape types); and a thr ee-position RECORD switch with settings labeled SAFE . READY, and MUTE . In additio n, there's a Dolbymode switch (with a copy and ON position that lets you use the built-in Dolby circuit ry for pur poses other than just tape recording and

MANUFACTURER'S PUBLISHED SPECIFICATIONS *: (' Items show n to eit her side of slash mar k correspon d to operation at Fl . ips/ 3'!. ips running speeds .) . Frequency Response (± 3 dB): 70)1s or Cr0 2 tape, 25 Hz- 19 kHz/ 25 Hz- 22 kHz. SIN Ratio. (A-Weighted): 70 )1S tape . 55/58 dB (Dolby off); 63/67 dB (Dolby on). Wowand-Flutter (WRMS): 0.05/0 .035%; unwe ighted, 0.09/ 0.06%. Harmonic Distortion: 70 )1S tape. 1.8/1.5%, at 0 VU record level. Fast-Forw ard or Rewind Speed (C-90): 45 seconds. Input Sensitivity: line, 200 mV. Output Level: 2 volts. Meter Type & Range: peak reading, - 40 to + 5 dB . Power Requirements: 105/ 135 vol ts, 50/60 Hz, 35 watts. Dimensions: 17"1,. W X 6% H X 10'1. inches D. Weight: 14.8 lbs . Suggested Retail Price : $529.95.


S()IJNI) _ _ _ _RATES



SUPERB Copy right 0 Gernsback Publications Inc., 1979

playback); and an M PX filter switch. That is useful when recording stereo FM program s off-the-air from tuners whose outputs contain significant subcarr ier high-frequency products that might upset Dolby operatio n and calibration, or might beat with the deck's bias oscillator: Three pushbuttons to the right of those switches select source of tape monitoring, intro duce a record-calibration test tone, and select microph one or line inputs. (M ixing of micro phone and line inputs is not possible with this deck.) Left and right microphone-input jacks, as well as a phone-output jack (stereo) at the lower right, complete the panel layout. Line-input and line-outp ut connections are both made at th e rear panel thr ough phono-tip jacks.

Lab measurements To evaluate and measure the two-speed deck 's perfo rma nce properly, we tr eated the unit as though it were two separate decks: one opera ting at a sta ndard I'I.-ips speed, the other at the increased speed of 3'1. ips. So many performance chara cteristics change when the speed is increased (all of them for the better, by the way) that we have shown our results for slow and fast operation separately. Table I summarizes our result s at I'/ .-ips operation, while Table 2 shows measurements obtained at the higher 3'/.-ips speed. We made all measurements using TDK-type AD C-90 cassettes as the "standar d" sample, while TD K-type SA C-90 cassettes were used for all measurements in the 70-microsecond equalization setting. As mentioned earlier , the manufacturer did not assign generic tape names to the three bias






s: OJ m



positions on the front-panel switch. They do, h o w ever , list recommended bias-switch settings for di fferent br ands and grades of tape. In many instances, the settings are not the same for high speed as they are for the standar d speed. For examp le, we fo und (and B .L e ./ Avnet reco mmends) that the high bi as setting should be used for TDK-SA tape (w hose bias requirements are similar to th ose of chrom e tape) at both low and high speeds. However, for t he T DK-AD tape we fo und t hat using th e low bias sett ing at slow speed and t he hi gh (not the normal ) setting at hig h speed yielded best overall results with respect to freque ncy response, signal-to-noise (S /N) ratio and distor tion. Since the Model T-3 is a three -head tape deck , we were able to cond uct sweep-frequency m easur ements (i n addition to point-by poi nt pl ots or tabu lat io ns) of overall record/ pl ay respon se. That was done for the TDK-SA tape at both t he slow-speed (Fig. 2) and highspeed (Fig. 3) m odes fo r - 20-d B and O-dB r ecord levels. The frequency -respo nse fig ures show n in Tables I and 2 are those we obtai ned at t he - 20-d B record level. The upper traces i n Fi gs. 2 and 3 show a particularly interesti ng ph enom enon: At the slow I 'I .-ips speed, the typical hi gh- f r equency rolloff caused by tape saturat ion occurs . In contrast, at the 3'1.-ips speed, even when the frequency sweep is made at a r ecord level of 0 dB, response remains virtually flat all the way out to 20 kHz! What that m eans is enormously increased headroom at high, frequencies, in additio n to othe r benefi ts (abundantly evi dent when you compar e t he measured dis to rtion, sig nal-to-no ise, and wow and-fl utter specs show n in Ta bles I and 2).


Manufacturer: B.I.C.!Avnet

CASSETTE TAPE DECK MEASUREMENTS AT W. IPS FREQUENCY RESPONSE MEASUREMENTS Frequency response, standard tape (HZ-kHz ± dB) Frequency response, Cr02 tape (HZ-kHz ± dB) Frequency response, other (see tex t) (Hz-kHz± dB) DISTORTION MEASUREMENTS (RECORD/PLA Y) Harm onic distort ion -3 VU11 kHz) (%) Harmonic distortion 0 VU (1 kHz) (%) Harmo nic distortion + 3 VU (1 kHz) (%) Record level for 3% THO (dB) SIGNAL-TO-NOISE RATIO MEASUREMENTS Standard ta pe, Dolby off (dB) Standard tape, Dolby on (dB) Cr0 2 tape, Dolby off (dB) Cr02 tape, Dolby on (dB) MECHANICAL PERFORMANCE MEASUREMENTS Wow-and-flutter (%, WRMS) Fast wind and rewind time , C-60 (seconds) COMPONENT MATCHING CHARACTERISTICS Microphone Input sensitivity (mV) line Input sensitivity (mV) line outpu t level (mV) Phone output level (mV) Bias frequency (kHz)

R-E Measurements 10- 19, 3.0 10-23, 3.0 N/ A See Fig 2 TDK-SAITDK-AD 1.2/1.2 1.3/1 .3 2.0/ 1.5 + 4.0/+5.5

R-E Evaluation Excellent Superb NIA

57 66

Excellent Excellent Very good Excellent

0.045 45

Superb Superb



Superb Superb Excellent Excellent

0.16 35.0 1.9 volts 317 / 8 ohms N/A

TRANSPORT MECHANISM EVALUATION Acti on of transport contr ols Absence of mechanical noise Tape head accessibility Constru ct ion and internal layout Evaluation of ext ra features, If any

Superb Excellent Good Excellent Excellent

CONTROL EVALUATION Level Indlcato r(s) Level con tro l action Adequacy of controls Evaluation of extr a controls

Excellent Very good Excellent Excellent Superb


TABLE 2 CASSETTE TAPE DECK MEASUREMENTS AT 3'/. IPS. FREQUENCY RESPONSE MEASUREMENTS Frequency response, standard tape (Hz-kHz ± dB) Frequency response, Cr02 tape (Hz-kHz ± dB) DISTORTION MEASUREMENTS (RECORD/PLA Y) Harmonic Distort ion at - 3 VU (1 kHz) (%) Harmonic distorti on at 0 VU (1 kHz) (%) Harmonic disto rt ion at +3 VU (1 kHz) (%) Record level for 3% THO (dB) SIGNAL-TO-NOISE RATIO MEASUREMENTS Standard ta pe, Dolby off (dB) Standard tape, Dolby on (dB) Cr02 tape, Dolby off (dB) Cr02 tape, Dolby on (dB) MECHANICAL PERFORMANCE MEASUREMENTS Wow-and -flutt er (%, WRMS) Fast wind and rewind time , C-60 (seconds) COMPONENT MATCHING CHARACTERISTICS Microphone Input sensitivity (mV) Line Input sensitivity (mY) Line outp ut level (mV) Phone outp ut level (mY) Bias frequency (kHz)

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By changing the spectrum analyzer's sweep mode from frequency log (as shown in Figs. 2 and 3) to linear (from approximately 0 H z to 20 kHz) , we were able to display the improve m ent gra phically in bot h SIN and thi rd -order di stor tion t hat is gained by increasing t he tape speed to 3'1. ip s. Fig ure 4 shows a I-k H z signal record ed onto t he TDK-SA sample tape (this sig nal appears as t he tall spike to the left in Fig. 4) . O n the r ight anot her spike represents

R-E Measurements 20-23,3.0 16-24, 3.0 See Fig. 3 TDK-SA/TDK-AD 0.8/1 .0 1.0/0 .8 1.0/0. 9 +7.5/+ 11.0

R-E Evaluation Superb Superb

59 61 69

Excellent Superb Superb Superb

0.025% 45

Superb Superb


See Table See Table See Table See Table See Table

Excellent Superb Superb Superb

1 1 1 1 1

TRANSPORT MECHANISM EVALUATION Action of transport controls Absence of mechanical noise Tape head accessibility Construct ion and Internal layout Evaluation of extra features, if any

Superb Excellent Good Excellent Excellent

CONTROL EVALUA TION Level Indlca tor(s) Level'c ontr ol action Ad equacy of controls Evaluation of ext ra controls

Excellent Very good Excellent Excellent




Model: T-3

OVERALL PRODUCT ANALYSIS Retail price Price category Price/performance ratio Styling and appearance Sound quality Mechanical performance

t hird-order or third-harmonic cont ent (3 kH z, in that instance), while the lower section of the photo displays the random noise content repr oduced dur ing playback . In the scope photo of Fig . 5, only the speed was changed, while the I-kH z recorded signal amp litude and all the gain and sweep settings remained the same . You will note that third- harmonic distor tion is meas ura bly lower and overall random noise level is considerably decreased throughout the bandwidth (to 20 kH z) .

Summary Recently, we had occasion to discuss the implications of met al-particle tape with one of the B.LC ./ Avnet engineers. As you know, pure metal-particle tape promises to deliver grea ter headr oom (or dynamic range) and improved frequency response especia lly when it is used in the cassette format. The B.LC ./ Avnet enginee r pointed out that operating a cassette deck at twice the so-called standard


Medium Superb Excellent Superb


Comments: With respe ct to the operation of the model T-3 at 3'1, Inches-per-second, It is not possible to compare this unusual stereo cassette deck with any other cassette deck available. As of this writing, there Is nothing that operates both at the higher 3'/, ips speed and standard cassette speed . We expected that the higher-speed performance of this deck would be much beller than the 1'/. ips performance of more expensive decks, knowing the limitations of slow speed tape recording. What we were not prepared for was the outstanding performance that this deck achieves even when operatIng at the slower standard speed . The design engineers could have opted for extended frequency response at the expense of other operati ng parameters. Instead, they wiselyelected to offer a machine In which allthe Important operati ng characteristics (I.e., SIN, distortion and frequency response) are beautifully balanced and optimized With respect to each other. At the deck's higher speed, its performance truly equals that of many open-reel machines. Of course, operating at twice the normal speed means that you use twice as much tape . In effect, a nominallylabelled C-90 casselle effectivelybecomes a C-45. To the serious recordist who wants the finest possible recordings, this will pose no great problem. And If you want to be miserly about tape usage , Table 1 confirms that even at low speed the deck maintains a level of performance for which you would have to pay considerably more with other decks. Aside from the supe rior measurements shown In Tables 1 and 2, we should note that such recording aber rations as contour effect (the tendency for low-frequency response to waver up to around 150 or 200 Hz) have been all but eliminated (see Figs. 2 and 3). The model T-3's mechanical performance is as impressive as its electrical performance. Although not solenoid-operated, transport control is smooth and positive, and tape handling is safe and reliable. B.I.C.!Avnet should be congratulated for taking this bold step in the casselle-deck marketplace .

speed prod uces exactly the same benefits without having to create new higher-bi as circui ts, new erase -electronics and heads, and new higher-capacity record ing heads. He furt her indicated that while operating cassette tape at twice the normal speed does indeed use up twice as much tape, the pure meta l-particle tape will cost considerably more than even the best grades of cassette tape present ly available. He believes the refore that the company's twospeed cassette tape decks negat e the act ual need for a bett er tape such as metal-part icle tapes . Of course , you can always arg ue that met al tapes, if used at higher speed in a compati ble cassette deck, would yield even fu rther overall improvement in performance .

Our overall product evaluation is cont ained in Table 3 along with some summary comments regarding this unusual cassette deck . If we have tended to concentrate heavily on the Model T-3's performance at its higher opera ting speed, that is because we were impressed by the observable difference s in performance compared with 1'/ , ips operation . The B.LC ./ Avent Mod el T-3 stereo cassette deck is indeed a superb piece of equipment even when compa red with ordinary cassette decks operated at the slow 1'/ , ips speed. Even if you conside r this equipme nt based only on the figures in Ta ble I, the deck is superb at its price; add the results shown in Table 2 and it becomes a trul y incredible machine . R-E

Solid State Ne\Ns Video mod ulator IC's

Motorola's MCI372 and XC1373 TV video modulators are designed for color TV applications in video games, data terminals, test equipment and videotape recorders. The devices can be driven by the MC6847 video-display generator and other color and video sources. The MCI372 is a 14-pin device with a chrom a subcarrier oscillator using an external 3.58-MHz crystal, a suppressedcarrier double-sideband chrom a modulator and an RF modulator. The lower-cost XC1373, mounted in an 8-pin mini-DIP, has an RF oscillator and dual-input modulator only. It can be used when a composite video source exists in another system . Both circuits produce signal outputs on

Channel 3 or Channel 4 and can altern atively produce inverted or noninverted video output signals. For details, write to Motorol a Semiconductor Products, Box 20912, Phoenix, AZ 85036. Second-generation VM OS device

Silicon ix's second-generation VMOS power FET, the VN84GA, is rated at 12.5 am p and 80 volts which is a six-times current increase over previous transistors. With only microwatt input power, the VN 84GA produces up to 80 watts output at low frequenci es and a 50-watt output at 30 M Hz. The devices do not show any of the secondary-breakdown and therm al runawa y characteristics of bipolar transistors. These FET's interface directl y with CMOS, TTL, DTL, and MOS families

for use in devices such as solid-state switching regulators, motor controllers , audio amplifiers and micro-processor inter faces. Using VMOS devices in linear amplifiers up to 30 MH z produces lower distortion because of the linear-transfer charac teristics and good high-frequency behavior of the VN 84GA, and the low distor tion means that only small amounts of feedback are requir ed. The devices can also be used in Class-D audio amplifiers because of their fast switching and zero storage time . Th e VN84GA is mounted in a TO-3 package and is priced at $19.76 in quanti ties from I to 99. Siliconix Incorporated, 2201 Laurel wood Road, Santa Clara, CA R-E 95054.



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VIDIOGAMI One integrated circuit equals ten action-packed games. Build this videogame and get in on that action. L STEVEN CHEAIRS BY NOW . NO DOUBT. A NUMBER OF RADIO·

Electronics' readers associate my name with video games . A fair portion of my articles thus far have dealt with that top ic-and in the pursuit of the tradition, here is another one. This construction project will provide the reader with ten more black-and-white video games. Both NTSC and CCIR televisions sets may be used; NTSC is the standard 525line U.S.A. system and CCIR is the 625line system used in many foreign countries. Both single-player and two-player games are possible. On-screen auto matic scoring has been provided . Two potentiometers, one for each player, provide for vertical paddle motion. A control voltage, determined by the setting of the potentiometer, charges a capacitor; the charge-level of the capacitor is detected by a Schmitt trigger. Thus the rotation of the pot causes a variation in the voltage across the capacitor that is detected and translated to a player-position on the tele vision screen. The player and his score are color-coded for easy identification. The audio circuit outputs tones to indica te hits of the ball by the player, and impacts with the court border or target obs tacles . Game selection is made by using a IO-key switch matrix; either fixed-t-or momentary-contact-switches are acceptable: Two switches are used to start the ball into motionand to keep it in play during the game. A reset switch is prov ided to clear the screen to prepare for a new game. Three other switches select skill-level options.













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FIG. 1-VIDEO DISPLAYS used by the Ten Action Games. The variations for Wipeout and Color Squares are shown in a. 13reakthrough 1 and 2 appear In band c.

first four games that will be described are the wipeout games. Figure l-a illustrates the different characters that can be generated when . playing the four versions of Wipeout

and the four versions of Color squares . Wipeollt I is chosen when select line one and strobe line one are connected, either momentarily or continuously, by switch S9. After game selection and






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About the games Five single-player, and five dualplayer games are contained on the LSI integrated circuit. Figure I shows a typical image for each game . There are three major types of game on that integrated circuit; those are Wipeout , Color Squares . and Breakthrough. The

THE HEART of the Ten Action Games board is the AY·3-8606-1 IC from Genemllnstrume nts. Many of the components clustered around It are used to set the parameters of the games and dis play.

R4 l OOK


R6 10K


Rl 10K

R9 Rl0 R11 R12 R13 R14 210n 1.2K 1.2K 3.4K 10K 10K

C4 C5 I ·33 I ·33 -e-=- 16

l C2 AY-3-8606-1 13 14





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FIG. 2-MAIN SCHEMATIC for the Ten Action Games. A fall pattern Is provided In Fig. 4.

game reset , the game is started by pressing either the right or left SERVE button (S5 or S6). The object is to hit eve ry blac k target-squ are . The squares disappear as they are hit. No deflection of the ball res ults from hitting a targetsquare . T he game will end if five consec utive misses occ ur or if all squares are hit and obliterated . This is a singlepla yer game- the right-hand paddle is used. That paddle is contro lled by the

pot co nnected neare st the LSI IC on the PC board. The score, paddle, ball, and boundary are gray. The score displays the number of targets hit. Wipeout II is also a single-player game ; it uses both the left and right paddles. After selection by S 12 (select I with strobe 2) and reset (S4), the game begin s when either SE RVE switch is depre ssed . It will start with a white ball moving toward the right side of the

screen. If intercepted by the black paddle, the ball changes color to black and rebounds tow ard the white side. The color-coded score record s the targets remo ved by its colo r ball. If select I and strobe 3 are shorted together by switch S14, then Wipeout III is selected. It is a two-player gameboth right and left potentiometers and SERVE buttons are used . The game is played much like the previous Wipeo ut game, but the playing area is totally enclosed. After the game is started it will continue until all target squares are removed . The first player to press his SERVE button after reset has control of the ball until his opp onent can intercept it, thu s gaining control of it for himself. The last Wipeout game , Wipeout IV, is chosen by S 16's connecting the select I pin to the strobe 4 pin. It is also a two-player game. The game is played generally the same way as the others but with one major distinction-the sc reen is divided by a large vertical barrier. Thu s the ball can only cross the field near the very top or bottom of the image and an added set of player strategies is gained. For example , once the ball is on a player's side, it may continually be boun ced off the barrier to gain up to half the possible points. To win then , one need only pass the ball to the other side of the playing field. At least one more point will be scored in doing so, winning the game. Color Sq uares games follow similar lines to the Wipeo ut set with one major exception-the screen is divided into four sections. Two quadr ant s are color coded as the white player' s and two are color coded as the black playe r's. Target de struction may only occ ur by ramming one's own color square. The game end s whe n all targets of one color are removed. Color Sq uares I. selected by connecting select 2 to strobe I (S8), is a single-player game. Color Squares




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r-----''''-----.., Switch No. S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 S13 S14 S15 S16


Pin NO'5.

High speed Ball size Bat size Reset Right serve Left serve Breakthrough I Color Squares I Wipeout I Breakthrough II Color Squares II Wipeout II Color Squa res III Wipeout III Color Squares IV Wipeout IV

~~ 12VAC o-+_..... <~ R5




o L-..t.l:.. VIDEO -----"'::!I 0 UT




AG. 3-CONNECTlON of case-mounted components to main PC board.

II is similar, but is a two- player version (it uses S II to connect select 2 and strobe 2). Color Squares III (select 2 and strob e 3-using S 13)is played much like Wipeout N. Select 2 and strobe 4 (S 15) tum on Color Squares N. That is a single-player game, with only one paddle; the field is enclosed on thr ee sides . The rem aining two game s are Breakthrough I and Breakthrough II. Breakthrough I (Fig. l-b) is a single-player game selected by switch S7. The ball is served toward the wall opposite the player's paddl e. When it hits the wall a block is knocked out. The object of the

game is to knock a hole through the wall and then to pass the ball through the hole . Each time the ball knocks a block from the wall it rebounds. The pad dle is maneu vered to intercept the ball and red irec t it into the wall. The wall is nine layers thick; only seven misses are permitted. The score , which should be kept as low as possible, records the number of blocks removed. Breakthrough II (Fig . l-c) is a twoplayer ga me with walls that are four laye rs thick. The game end s when a breakthro ugh occurs. Winning is a func tion of the numbe r of hits. That

1 + - - - - -- - - -- --


game is turned on by the select 3 pin and the strobe 2 line (S 10). No game selection occurs when select 3 or 4 are shorted to strob e 3. Some features are common to all the games . The targets are arranged in a 4 x 6 array. Each target is eight raster lines high and four dots wide. The score display is sixteen lines high and six dots wide. Each vertical line is two dots wide and each horizontal line is four ra ster-lines thick . The ball can be . eithe r of two size s, five lines or nine lines high-switch S2-and the bat size a nd ball speed are selected by S3 and S I, respectivel y. The audio signals are the same for all the games. Construction Thi s project is relatively simple for the beginner. But, even so, a minimum level of skill in con struction is assumed. There are a number of sources (such as back issue s of Radio-Electronics) where the beginne r can find information on cons truc tion techn ique s.

--5-5/8 INCHE S - - - - - - - - - - - - - - -. .



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15 « a:


21, Gnd . 20, Gnd . 19, Gnd . 18. Gnd . 17, Gnd . 12. Gnd . 25. 26 25. 27 25. 28 24. 26 24, 27 24, 28 23. 27 23. 28 22. 27 22. 28





• AG . 4-PC BOARD foil pattern. Dots In co m ers Indi cate position of mounting holes.

PARTS LIST All resistors V4 watt, 5% unless otherwise specified Resistors R1- 150 ohms R2- 12 megoh ms R3-220 oh ms R4. R5-100.000 ohm pot . li near taper R6. R7, R13. R14, R18- 10.000 oh ms R8- 1000 o hms R9-270 ohms R10, R11- 1200 ohms R12- 3400 oh ms R15- 1600 ohms R16-1800 ohms R17- 470 ohms R19-2200 ohms R2G- 10 ohms R21-R2 4- 100.000 ohms Capacitors C1-250 /IF . 25 volt electrolytic C2. C3-2.2/lF. 25 volt tanta lum C4. C5-0.33 IlF ceram ic C6. C7-30 pF cer amic C8-C13-0.1 IJF ceramic Semiconductors 01 -04-- 1N4003 0 5-6.8-volt Zener dio de Q1-2N3904 Q3-2N3906

IC1-4001 CMOS quad . 2-input. NOR gate IC2-AY-3-8606-1 (Generallnstruments) fo r U.S.-sta ndard video (525·line) or AY·3·8606 for 625-line standa rd XTAL1-3.579545-MHz crystal S1-S3-S PST togg le switch S4-S16-SPST normally-open (N.O,) pushbutton switch T1-12-volt. t-amp transformer Miscellaneous: case. 8-ohm speaker , line cord, output jack. four spacers . wire . hardware. The following may be obtained from Quest-Star Electronics Co., 5412 Burntwood Way, Las Vegas; NE 89108: Kit with all parts (no case or hardware) , U.S. standard, G1300, 555.00 or 625-line standard, G1301, 557.00. PC board only, 512.00. AY-3-8606 or AY-3-8606-1 , 514.50. For orders of 25 or more contact Quest-Star for prices. Please add 52.25 for shippingany excess will be refunded. Nevada resident s add 3V2% tax. Shipment will be made from stock to six weeks .

• 12VAC IN


2N3906 OR 2N3904

,I' B~ FIG. &-PARTS PLACEMENT DIAGRAM. Take care to observe all polarltles and make sure that jumpers are Installed. Do not confuse the 2N3904 and 2N3906 transistors.


SUGGESTED LAYO UT for the PC board and external components within the case. The array of switches at the top Is co nnected to a row of pads located lust above the game IC.


FIG. 6-RJNCT1ONAL PINOUT of the AY~1 IC. This can help you with the off-the-board wiring and, should It prove necessary, in troubleshooting.

The basic tools one will need are a fine-tip, low-wattage soldering iron (about 27 ~ watts) , a pair of fine-tip pointed-nose pliers, a pair of diagonaltip wire cutters, and a set of wire strippers. Also, include a spool of rosincore solder. The game, may be assembled using point-to-point wiring, wirewrap, or printed-circuit techniques. The printed-circuit approach will be considered here . The other two methods can be undertaken using the parts list and the schematic diagrams shown in Figs. 2 and 3. Table I lists the function s of the front-panel mounted switches and their connections. If the printed-circuit approach is cho sen then one can etch his own card using the artwork pattern presented in Fig . 4, or a board layout may be made by referencing the schematic diagram. The simplest course is to buy a readymade circuit board from the source given in the parts list, Quest-Star Electronics Co . The first step is to obtain all of the components shown in the parts list; most of those are common items . The main LSI game IC may be a bit difficult to find, but it might be obtained from the same source as the PC board. Also , Quest-Star will provide a complete kit of all parts for those who do not have access to all of the components or who want to simplify their shopping. The complete kit includes all of the electronic components, the PC board, and the required hardware . Ha ving collected all of the parts, place all of the electronic components on a workbench, desk , or table. Make sure that all of the MOS and CMOS integrated circuits remain in their conductive packaging. Compare the components, now laid out, to the items specified in the parts list and if everything matches then proceed. Take the enclosure and drill the holes required for the potentiometers, switches, transformer, PC board,


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speake r, video-output jack, and linecord . Next, paint the exte rior of the case . Afte r the paint is dr y use drytransfer lettering to label the controls. Th at should be followed by spraying the case with a clear lacquer to protect the finish. Let the case dry for 12-24 hou rs. Mount the comer spacers on the foil side of the printed -circu it board. Install the IC sockets in thei r proper location s-making sure they are oriented pro pe rly; Fig. 5 should be cons ulted. Place a piece of cardboard on top of the sockets and invert the assembly, kee ping an even pressure on both sides. Now solde r the sockets into place. Retu rn the assembly to the components-side up posi tion. Inst all all of the res istors and capacitor s ; verify their locat ions and solder. Next insta ll the diodes, transistors, and vo ltage regulator. Again verify the orientation and place ment of the parts before soldering. Lay the PC card aside until fina l assembly. Whe n the case is dry, mount the co ntro ls, transformer, line-card, output jack, speaker, and PC card. Wire those com ponents as shown in Fig. 3. Before pro ceeding verify the wiring! Plug th e line cord into an AC wall outlet. Check the voltages at the IC + V pins fo r the proper DC level- about 5 vo lts . If they are correct, unplug the cord and disc ha rge the capacitors. Install the Ie' s in their socketsobserving the proper orientation . The assembly is now comp lete; if an RF modul at or is to be used it may be also installed in the case. Troubleshooting Th is se ction, I hope, will never be needed but if pro blems should be enco unte red use the schematic diagram and the pinouts provided in Fig. 6 to aid in tro ub leshooting the game circuit. Start by following the checklist below: 1. Are al l compone nts in t he proper location? 2. Are all com ponents o riented correctly? 3. Is the PC card w ired cor rectl y to th e exte rn al co mponents? 4. Is th e pow er -supp ly volt age co rrec t? 5. Is a 3.58 - MHz clock sig nal pr esent at pin 9 of th e ga me IC ? 6. Is there an audio output ? 7. Is th ere a composite video sig nal ? (f)



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If the an swer to any of the se que stions is "no," then investigate that portion of the circuit. For examp le, if no clock signa l is observed, check the oscillator. Troubles hooting in that fas hion s hou ld enab le you to locate and remedy any problems rath er quickly. You s hould obta in a great dea l of enjoyment from both the construction an d use of this project. R-E




nism is a complex one, and so are the electronic circuits that co ntrol it. Let's take a look at how those control circuits work . A prime key to the operation of the control circuitry lies among seve ral switches. They open and close at what may seem irregular times during the tape -threading process. But the timing is quite specific, as you will see. Act ually, on ly two switches (see Fig. I) work odd ly. They operate as follows: While the machi ne is in the STOP mode-that is, befo re any butto n is depressed- the play- I switch is ope n, and the play-2 switch is closed . When you first press dow n the PLAY button, the play -I switc h closes. The pla y-Z switch remains closed, for that initial movement of the PLAY button. However, by the time the PLAY button reaches the bottom of its tra vel and latches, the play-2 switch has opened . Later, pre ssing the STOP button unlatc hes the PLAY button. As the play linkage leaves the latched-down play pos ition, the linkage closes the play-2 switch . . . and shortly thereafter opens the play- I switch . The sw itches ju st de scribed initiate the loading operation . To shut off the threading motor when loading has reach ed its limit, a loadin g-end sw itc h c loses and applies 12 volts to transisto r Q6l2. Th e sw itch, ha ving closed when loading is finished , remains closed unt il the motion of load ing actually begins . Unloading is initiated whenever the PI..-\. Y button unlatches , whether it is done manually or by the aut o-shutoff so le noid. As you already know, this

action of the PLAY-butto n linkage closes the play-2 switc h and ope ns the play-I switch. Then , when unloading is co mpleted, the un load-end switc h closes. That grounds the cat hode side of diodes D617 and 0 618, which redirects voltage s aro und so the motor quits running. The unload -end switc h stays closed until such time as the PLAY button agai n starts a loading operation. In one variation appearing in rece nt VHS mode ls, the loading -end switc h clo ses a pat h to ground instead of to a voltage supply. Of course, circuitry changes somewhat . For operation of the remai nder of the sec tio n, however, that modification changes practically nothi ng. Tape loading To initiate tape loading, the operato r depresses the PLAY button on the front of the machine . Switch play- I (see Fig. I) clo se s immediately . When the button is first pushed, switch play-Z rema ins closed. A DC voltage goes throug h the playI switch to a voltage divider (R633R634) at the base of Q6 11. That turns Q61 1 on. The voltage at the collector of Q6 1l goes low. In digital terms, logic high at the base of Q6 1l produces a logic low at the collector-a classic inverter action . The low voltage (logic) coupled to the base of Q610 through R632 places a logic high at the Q6 10 co llector and a logic low at its emitter. Both are output point s from that stage . Low bias at the base of Q609 leaves Q609 cut off. A logic high co uld devel op at the co llector if the re were some path for DC from a supply point. As

Many videotape deck service problems involve the load/unload section. This companion piece to one which appeared several months ago on the Beta mechanism will round out your knowledge and abilities. you see, however, there is no supply resistor . . . onl y Q608. The P colle ctor of Q6l 0 is supplied with 12 volt s unregulated through R623 a nd R624. With no drop across R623, because Q610 is cut off, the base of Q607 stays high, sa me as the emitter. Lack of forw ard bias leaves this PNP tr an sistor cut off. Q607 is, in effect, op en .

Meanwhile, the play-2 switch has rem ained closed . (This is still during the first instant of depressing the PLAY button.) The unlo ad-end switch, too, is closed, left that way when the tape last unlo aded from the transport mechanism . These two switches cre ate a path to gro und for th e positive voltage coming thr ough R618. A ground at the cathode of D6l 8 forward-biases D61 8

and then D6l9. The voltage at the junction of R6l8 and D6l9 stays near zero as long as both switches remain closed. Hence, Q605 receives no forwa rd bias (logic low) and stays cut off. The result ing low voltage at the emitter of Q605 is seen as a logic low by the base of Q606. SO that transistor, too, remains cut off. A DC supply path ex ists for the col-

0611 PLAY 1 +12V ~o--_---+----, R618 UK

R632 3.3K R622 4.7K

0619 PLAY 2 0618





e61 9 270pF

R619 3.3K

R624 330n

0616 0605

':'R635 47K




R620 2.2K ':'

+12V ':'




R623 3.3K ':'

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MOTOR ·+12V UNR EG FIG. 1. SWITCHING DIODES AND TRANSISTORS turn threading motor on and off, and apply voltages in reverse for unloading. Limit switches turn the threading motor off at the end of the loading and unloading sequence.



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lector of Q605. It sta rts at the fusible resistor and the 12-volt unregulated line. Resistors R627 and R628 complete the path. But with Q605 cut off. no cur rent flows through those resistors, and no voltage drop occurs. The volt age at the base of Q608 stays at the same level as the emitter. and Q608 remains cut off. too. All that has taken place in the instant the PLAY button was first pressed downward . clo sing the play-I switch. Ne xt , the PL AY button latches at the bottom of its tra vel. At that extreme, the playbutton linkage opens the play-2 switch. Now things begin to happen. A bias voltage for Q605 now develops across R620. Transistor Q605 turn s on. Current flows in the R621-Q605R628-R627 path from the 12 volts unregulated line. A positive voltage develops ac ross R621. which turn s on Q606. The normally-negativ e motor terminal goe s to ground through a conducting Q606. Current thr ough R627 de velop s a bias th at leaves the base of Q608 less positive than the emitte r. That bias turns Q608 transistor on. which applies 12 volt s DC to the norm ally-positive terminal of the loading motor. The motor begins turning. in its " forward" or normal direction. The mechanical loadin g proce ss thu s begins. The unload-end switc h opens as soon as the load ing-drive mechanism turns the loading rings. But that has no immedi ate effect on anything electronic. The play-2 switch opened earlier. when the PLAY button latched. And D617 is reverse-biased anyway. because Q61 1 is conducting heavily and keeping its collector voltage practicall y at zero .





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End of loading The threading motor operate s the tape-loading mechanism. Eventually. the loading-ring posts reach the limit of their travel . coming up against their V-stop s. A protrusion on one ring pushes an arm that closes the end-of-loading leaf switc h. If the switch is the kind that applies 12 volt s to R635 and R636. as is shown in Fig. I. the bias turn s on transistor Q612. A highly conductive Q612 acts as a short at the junction of D618 and D619. Diode D619 becomes highly conductive a nd the voltage at the jun ction of R618 and D619 goes to zero . Th e bias on Q605 ceases and Q605 cuts off. Lack of current th rough R627 now lets Q608 cut off. removing DC voltage fro m the positive termin al of the moto r. Lack of curre nt thr ough R621 cut s off Q606. which removes the ground path from the negati ve termin al of the motor. Eithe r change stops the motor from turn ing. Note that Q6 11 stays on. This, through Q610. keeps Q609 and Q607 cut off.

The unload cycle To initiate unlo ading in VHS mac hines . the operato r need only press the STOP button. Th at has no direct electronic effect. It merely unlat che s the PLAY button and allows it to return to its up position . Th e play- I switch ope ns and the play-2 switch closes. Th e play-2 switch has no effect. becau se the unload-end switch has remained open ever since load ing began. The play-I switc h. upon opening . remo ves voltage from R618 and R633. The bias for Q611 disappear s. Transistor Q61l, which has been on all this . time, turns off and triggers a whole chain of electronic events. The voltage at the collector of Q611 rises to the supply value . The positive voltage (logic high) goe s through R632 to the base of Q610, turning Q610 on . Current through R629 place s a positive bias on Q609. and that transistor beco mes highly condu ctiv e. Transistor Q609 thu s effecti vely grounds the normally-po siti ve terminal of the loading . motor. Turning on Q610 brings its collector voltage low . Current flows in supply resis to rs R624 and R623. The voltage drop across R623 make s the base of Q607 less positive than the emitter. T ran sistor Q607 turn s on. applying the positive 12 volts DC at its emitter to the norm ally-negati ve termin al of the motor. Th e loading motor, with voltages applied in opposite polarity to "normal." begin s turning backward . That sta rts the threading mechanism unloading the tape. As the loading rings rotate away from the "loaded" position . pre ssure is released on the loading-end switch . It opens. But that has no immediate electronic effect. When the play-I switch opened, voltage was removed from R6 I8. Diode D619 was from that moment no longer forw arded-biased, so there was no longer a voltage path through Q612 anyway . The loading-end switch ju st rests open until another loadin g cycle ca lls it into use . Opening the play-I switc h also removes the voltage from the R618-R619R620 divider. With no positive bias, Q605 ca nnot conduct. Lack of current leaves no voltage across R621, and no bias for Q606. which stays cut off. By the sa me token , the re' s no cu rrent flow th rou gh R628 and R627; the base of Q608 stays as positive as the emitter and Q608 rem ains cut off or open . End of unloading So me other electronic effects have developed durin g the unload cycle . T ransisto r Q611 is off, and its collector vo ltage increases in the positive direction. Th at places a positive voltage on the anode of D617. Howeve r. it doe s

not con stitute forward bias , because there is no ground return . So far, the unlo ad-end switch is open. But when the threading mechanism reac hes its limit, one loading ring moves an a rm that clo ses the unload-end leaf switch. No w D617 can conduct. And it pulls the voltage at the collector of Q61l to ze ro. With bias gone , Q610 turn s off, and so doe s Q609. That removes the ground from the positive motor terminal. Current stops flowing through R624 and R623, leaving Q607 without forward bias either. Transistor Q607 no longer applies a positive voltage to the other motor terminal. The motor stop s. Tape has been unlo aded. The unload-end switch remains closed until the next load cycle begin s. Safety during threading Several conditions that trigger automatic-stop have the same effect if they occur during threading. Moisture on the dew detector or a stopped videohead wheel or capstan will prevent load ing. T he auto-stop mechanism unlatches the PLAY button, letting it return to its up position. That triggers the unlo ad mode and unloading proce eds in the manner ju st described. Other safety fac tors are built into the electronic circuits of the threading/ unthreading sec tion. A time-del ay senso r, for example, halts loading efforts if an ything impedes loading for more than 4 or 5 seconds. Two seconds should be sufficient for norm al loading. You ca n follow the working of that misloadin g protection arrangement by following Fig. 2, which contains additional control circuitry not shown in Fig. I. When the play-I switch closes, it applie s volt age to R638. However, the still-closed play-2 switch ground s out that volt age at the other end of R638, by holding D618 and D620 in conduction . But when the play-2 switch open s (as the PLAY button latches), the ground path through D620 and 0618 then disappears. Diode D621 then conducts. So would D626. which ac tivates auto- stop, were it not for cap acitor C606. When voltage first reaches the D621-D626-C606 junction. it goe s ve ry low as the capacito r begin s ch arging. Diode D626 therefore cannot conduct. It take s several seconds for C606 to ch arge up through R638 and R639. After that time , however. the voltage across C606-R639 incre ases enough to make D626 conduct. And that sends a logic high to the auto-stop syste m, activating it. The purpose is to stop the loading in ca se something jams the thre ading mech ani sm. When loading proceed s as it should. the loading-end switch clo se s we ll before C606 reaches any-



+12V ~o--""'----------1--+----' R618 4.7K

PLAY 2 0616



R633 lK R634 220n


R622 4.7K



0616 R619 3.3K


R626 330n


0626 0649



0605 0646


R639 220n

R637 12K

R620 2.2K

C604 4.7"F

R635 47K 0612 R636 15K

+12V '="

FIG . 2. THE CH ARGING TIME of C606 through resistors R638 and R639 delays the voltage rise on 0626, to give th reading t ime to co mp lete before the auto-stop mechanism is tripped.

where near a full c harge . . . before the voltage attains a level that could make D626 conduct. The loading-end switch tu rns on Q612, through the bias applied by R635 and R636. Conducting heavily, Q6 12 gro unds out the voltage at the D620-D62I end of R638. Insufficient po sitive voltage rea ches the anode of D626, thus averting auto-stop action. Powe r interruption, such as linevo ltage failure or even turn ing off the main power switc h of the mach ine, tr iggers the auto-stop sys tem. That occurs through an effect which takes place in anothe r portion of the transport control electronics. Figure 3 shows how. Transisto r Q631, which is part of the head-wheel-rot ation det ection syste m, draws its collecto r voltage from an unr egulated 18-vo lt supply. Base bias, howe ver, comes from the power-on line, that ca rries 12 volts from the main power supp ly. An ou tput filte r capac itor on the 18vo lt line in the power supply (C III , 4700 !.L F) stores a conside rable charge . When the powe r is inte rrupt ed, base bias on Q63 1 disapp ears immediately, a nd Q63 1 cuts off. T he co llector voltage on Q63 1 increases acc ordingly. The 18-volt supply does not diminish so quickl y, due to the la rge amount of e nergy stored in the power-suppl y capacito r. Diode D629. rece ives a high positive

voltage on its anode and conducts. Resistor R644 car ries a logic high to the auto-stop section. To assure quick auto-stop reaction, ca pacitor C607 and resistor R648 couple the abrupt rising pul se at the collector of Q63 I to an advance d stage in the auto-stop section. Th e auto-stop solenoid operates, making the PL AY button pop up immediately upon interruption of power to the main supply. Th en, when power is reapplied , the threading-cont rol system has been set for unloading. So unloading occurs, no matter how far thread ing had progressed when power went off. Troub les hooti ng load/ unload faults As with other electromechanical operations in a VCR, you generally TO 0632 AN0 0633 R644 0629 10K POWER ON +12V R6921 3.3K

- - "'*C111 14700IlF ..!:-

+18V UNREG -

FIG. 3. POWER·SUPPLY CAPAC ITOR C111 pr ovides power to Q631 long enough for 062 9 to activate auto-stop aft er a power fail ure.

fa re best when you analyze mechanical functions before tackling the electronics. Even though most operations are comm anded by electronics, their faults often show themselves mainly in mech anical ways . Having observed movements (or non-movement), you can more readily assess what electronic stages are at fault. Evaluating some ordinary symptoms probably explains best how to diagnose wisely. Will not load. Make sure the PL AY button latches. If it doe sn't, check its mechanical latch. The stop solenoid could be tripping the PLAY button; make sure the plunger or a linkage is not stuck. If the solenoid trip s the PL AY button electronically, determine which transport safety sensor is activating automatic shutoff. That calls for electronic tracing; yet , the auto-s top action might be caused by a mechanical malfunction. There is no escaping the interrelatedness of electronics and mechanics in a video ca ssette recorder. Observe the opening-closing seque nce of the leaf-type limit switches . Some have a protective cover that you must remove first. Inspect the Play switches , accessible if you open up the bottom circuit panels (see Fig s. 4 and 5). If you doubt that any switch is making contact, use your voltmeter or ohmmeter to verify the switches continuity. If ,eve rything mechanical appears okay, but the machine will not load , start electronic diagno sis. You ca n begi n at either end, but sta rting at the motor is generally quicker. A DC voltmete r is your most suitable tool. A logic probe can be used , pro vided you have learned to think in logic high/low terms. When components are discrete rather than IC, most technicians .tend to fee l more comfortable with regular vo ltage measurements. Latch the PL AY button down . With ground as a reference , measure voltage first at the norm ally negat ive ter minal of the motor. The Voltage there should be zero. If it is high, Q606 may not be conducting. But do not overlook the possibility of a defective contact in the interchassis plug for the motor wiring. Pull the motor plug from its socket. Mea sure across the motor termi nals with your ohmmeter. Around 20 ohms is normal. Another trick: Connect your voltmete r across the unplugged motor. Sp in th e flywheel by hand. A norm al DC motor ge nerates a DC voltage when turned by an external force; the output voltage is positive when you spin th e shaft in one direction. negative in the other. Check bias on Q606. and verify that Q605 wo rks. If bias is missing from Q605 th e play-2 switch may not have opened . Thi s micro switch is actuated with a bar pushed by the PL AY button linkage. If the switch stays closed. the



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ground path through 061 9, 061 8, and the unload-end switch keep s the voltage at the ba se of Q605 low . Anything that ultimately keep s Q606 from conducting can preve nt the motor turnin g. Transistor Q606 acts as an open circuit inste ad of as a ground con nection. Check the DC voltage at the normally-positive moto r terminal. Assuming Q605 conducts as it should, check the bias on Q608, across R627. If you find that Q608 operates normally, but the voltage at the plus side of the motor is low, check whether a leak y Q609 might be dragging the voltage down at the collector of Q608. Or , Q609 might be turned on . Tr ace back to find out why , becau se Q609 should be off during loading . Tran sistor Q610

should also be cut off. The appearance of bias at the base of Q610 could indicate that 0 617 or the unload-end switch is open. A defective Q611 would not leave the bias voltage on Q6 10 high, becau se a prop erl y funct ioning 0617 a nd the unload-end switch (still closed , until loading motion actually begins) holds down the voltage co ming tnrough R622. Another possible fault lies in the loadin g-end stage. Should Q612 short, the 0618-0619-0620 junction stays at zero. Diode 0619 prevents any voltage from reaching Q605, so Q606 and Q608 remains cut off. Loadin g therefore ca nnot occu r. (An open or nonoperative Q612 leaves the load ing motor on. You may hear a squeaking as

AG. 4-THE PLAY-l MICROSWITCH closes when the PLAY button Is depressed.

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FIG. 5-THE PLAY-2 MICROSWITCH, pushed by a mechanical slide link, opens when the PLAY button latches.

the motor pulley rubs the unmoving dri ve belt.) Will not unload. The stages involving Q605, Q606 and Q608 must be okay, since th e . tape loaded. Howe ver, -an open Q609, Q6l 0 or Q607 might disable the unloading sequence. Again, sta rt at the motor with your voltmete r. A missing positive voltage at the normally-negative side of the motor indicates that Q607 is not conducting a positive voltage from its emitter to its collector. !\. positive voltage at the normally positive terminal is wrong when the machine is tryin g to unload. That symptom suggests that Q609 is open or not conducting. A positive voltage at both terminals confirms that Q610 and Q607 are working and that the motor and plug show continuity. Transistor Q607 would stay off if Q610 were open or cut off. If there is no positive voltage at either side of the motor, you should suspect that Q610 is defective. However, a shorted Q6l1 or a stuck (closed) unloadend switch could prevent unloading, even though the loading has proceeded normally . Intermittents, Erratic loading or unloading can give you fits. Once you disco ver which function fails, the hints already given tell you in which stage s the fault might be . Intermittents tend to fall into two categories. One is a cold-soldered connection between some part and the circuit board. An insulated pokingprobe can help you find these . Or, if all else fails , take a hot soldering iron to each connection in the stages likely affected . The other most common intermittents tum out to be in the connecting plugs . The quickest cure, ordinarily, lies in ju st unplugging and replugging each connector tightly. But inspect the female side of the plug. A damaged wiper can spoil the connection at one pin; that is not uncommon if someone else has been "into" the machine before you. For your own part, be exceedingly careful when plugging a connector back into the pins of the circuit board . One bent wiper and yo u' re the cu lprit. That darriage can be hard to trace , and the cure ju st might be a new plug. Loads, then unloads, This symptom corresponds with automatic shutoff. The PLAY button pops up and the inachine unloads. If the tape fails to unthre ad , you have an unloading problem, too. Should an ything interfere with completion of the loading motion, the loading-end switch doers not tum on Q612. After the time-delay interval, ' shutoff takes over automatically. Hunt for that trouble in the loading sequence, or in any of the sensor stages. R-E

An in-depth look at

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There's no end to all of the control you've got. You can turn on the TV, radio or stereo in the morning to help you wake up without getting up from bed. Or at night, turn on the lights before going downstairs so you don't have to fumble in the dark. Turn off unnecessary lights and help get your electric bill under control. Or, dim the lights and save energy, too . And when it's time to turn in, just push a button and turn everything off. And sleep soundly. But, if you hear a strange noise in the middle of the night , you can press a button to turn on all the lights and scare the daylights out of an intruder.

The Controller is designed to control every room in the house. By pressing the buttons on the Command Console keyboard , command signals are transmitted over

the modules . And you're ready to take control.

existing household wiring to he module of your choice . The Lamp Module turns on, off or dims any incandescent lamp up to 300 watts. The Appliance Module turns appliances like TVs, window fans or stereos on and off. And the Wall Switch Module is designed to turn on, off or dim any light or lamp up to 500 watts normally operated by a wall switch . There 's even a Cordless Controller that transmits signals to an Ultrasonic Command Console from up to 30 feet away. So there 's plenty of control for everyone.

Simplicity is built into the system.


No special wiring is needed . Simply plug The Controller Command Console into any wall outlet in any room of the house. Then plug your lamps and appliances into the appropriate modul es. Plug in


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- - - -_.


_. -



----- -

Q;f!!W: .id.~a's ~


- -


- _.

movement s are on th e orde r of 1800 ohms and the inpu t imped an ce of the alert is in the megohm range. Thi s device is as versa tile as your met er, since all it reacts to is th e metermovement dri ving voltage. It will respond to a change in AC or DC voltage, current, or in resistanc e. Yo u t ell the Trouble Ton e Alert whether to look for an increase or decrease by mean s of the DPDT switch and adj ust th e threshold control until th e tone from the Son alert ju st disapp ear s (with th e meter in th e circuit being tested , of course) . Afte r that you can go about your busin ess and wait for th e alert to signal you when your intermitt ent probl em has finally shown up. John J. Augustine


for use in my service business, and it works great. I use it to look for int ermittent problems on my bench . For exampl e, if I had a color TV whose hori zont al output current would go way up at unpredictable times, and I didn 't want to sit by and wait for this to happen, I'd hook up the tone alert and let it tell me when the current increase took place . The Trouble Tone Alert is intended for use with analog meters-just wire a " mini" earphone jack dire ctl y across the meter movement, plug it in, and you' re all set. The high imped anc e of the alert keeps it from affecting the accuracy of the meter reading, because most meter

- -






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NEW IDEAS This column is devoted to new ideas, circuits, device applications, construction techniques, helpful hints, etc. All published entries, upon publication, will earn $25 plus a Circuit Board Holder, Standard Base and Tray Base Mount from Panavise Products, Inc. (See photo below.) Selections will be made at the sole discretion of the editorial staff of Radio-Electronics.


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I agree to the above terms, and grant Radio-Electronics Magazine the right to publish my idea and to subsequently republish my idea in collections or compilations of reprints of similar articles. I declare that the attached idea is my own original material and that its publlcation does not violate any other copyright. I also declare that this material had not been previously published.


FIG. 1

Title of Idea Signature Print Name









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Mail your idea along with this coupon to: New Ideas Radio-Electronics 200 Park Ave. South New York, NY 10003


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h~bby c~rner

One-arm bandit circuit plus a new packaging system for your projects. EARL "DOC" SAVAGE, K4SDS, HOBBY EDITOR HENRY COOPER OF STERLING HEIGHTS,

Michigan, has come up with an interesting circuit for a one-armed bandit. There are a number of such circuits around but his is much simpler than most. Figure 1 is a "cherries/lemons/oranges" circuit based on the one Henry sent in. When I built his, I managed to eliminate a few more components. The present count seems to be about the minimum number of pieces that will do the job.

each case, the D, E and F segments are on, so he wires them to stay on and doesn't have to worry about controlling them. That leaves only A, B and C segments to control-actually, only two since Band C must go on and off together. The G segment (the center horizontal one) is not used in any of those three displays. The Band C segments are driven directly by the 7490's . Driving the A segment directly would have it on when it should be off and vice-versa. That is the

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want the players to be able to see the readout befor e releasing SI! A little experience with the bandit may cause you to want to change the odds. That can be done by changing the 7490 output pins used to drive the segments and/or the next 7490. Output pins are 12 (I), 9 (2), 8 (4), and 11 (8) . Experiment with various combinations. You don't have to drive the A segment and the next 7490 from the same pin, either.

The readouts are 7-segment commoncathode LED's. Since the circuit wiring is somewhat unorthodox, the LED 's are shown in an "exploded" view to prevent confusion . The 555 serves as a stand ard astable (free -running) multivibrator that we have discussed before. It drives 7490 counters-s-one for each "window" LED. That is where the present circuit departs from the usual. Henry's LED 's read "C" for cherry, "L" for lemon and "0" for orange. In

This little bandit works very well. Build it in a small case such as the Unibox mentioned below and it will provide many hours of entertainment. To get it into the smallest possible box and have the greatest convenience, use a small wall-plugtype AC adapter. If you build in the 5volt regulator shown in Fig. 2, you can use a common 9-volt adapter. Of course, you could also use a 9-volt battery but it won't last long because of the heavy current drain of the readouts. Thanks, Henry, for sharing your circuit with us. Packaging your project

purpose of the inverter (one-sixth of a 7404)-to reverse the on/off action of the A segment. When building the bandit , you may wish to examin e the readout action more closely. As given, you won't be able to see what is happening while SI is pressed because the 555 is running at a rate of about 500 kHz . Increasing the value of RI and/or Cl will slow it down. Don't forget to put it back to high speed when it is operating to your satisfaction. After all, you don't

As soon as you think you have found an ultimate product-s-one which cannot be improved-someone comes along and does just that! This time it is small cases/ cabinets for electronics projects. Amerex (P. O. Box 2815, Riverside, CA 92516) is the outfit that has made the improvement with their Unibox (Figs . 3 and 4). One would expect the choice of colors and sizes (in this case up to 2 X 4 X 5'/, inches) in those tough plastic enclosures. Several other Unibox features, however, are not expected . First, there are epoxy-glass gridboards that mount vertically and/or horizontally inside. Those grid boards are perforated in the standard O.I-inch hole pattern for easy mounting and wiring of IC's, sockets and other components. Next, there are red or gray windows for use with LED and other readouts. Then, there are opaque panels that can be used for connectors, switches and so on. The final touch is provided by non-marcontinued on page 82

The sharpest p icture e ver a chie v e d in big-screen projection TV

The only computerized home weather station lor instant. up-toth e-minute weather reports

The new Heathkit Screen Star sets a new standard in picture quality for big-scr e en projection TV. The finest Fl.O lenses you can buy produce one of the clearest, brightest pictures ever. Imagine watching all you r fa vo rite TV movies and sports e vents on a big 6-foot diagonal screen. Heathkit's th ree -tube projection gives you brighter, more vivid color. And it's a lot e a s ie r to build th a n conventional TV's . I

Jus t push a button for reliable weather in formation a nytime you need it with the u nique Heathkit Weather Station. It gives you digital readouts of For C temperatures, wind speed in miles or kilometers per hour or in knots , wind direction, barometric pressure, date and time of day, even the wind chill factor. This microprocessor-based weather computer has memory to store data and precision infra-red sensing devices built into the outdoor transmitter. And it's very easy to build.


A complete com p ute r syste m In one compact unit The Heathkit All -In-One Computer ta ke s the guesswork ou t of selecting a balanced computer system. It includes built-in floppy storage, smart termin a l. heavy-duty ke yboard, 12-key numeric pad, Z80 CPU , and 16KRAM expandable to 48K-all in one compact unit . Two Z80 microprocessors mean te rminal and computer never share power. So both can operate faster on more comple x programs. And there's no better way to learh about computers tha n to build one yourself .

The l inest stereo receiver ever introduced by one 01 the le a ders in audio technology It's loaded with luxury features that let you adjust your music to your preference. Special featu re s include a Precision Tuning System (PTS) that crutomtrtically corrects mistuning . 5-section FM tuning capacitor gives you maximum rejection of unwanted signals for lower noise, cleaner sound. Digital frequency readout. center tune meter, and flywheel loaded tuning are just a few of the luxury touches . Complete specifications are in the latest Heathkit Catalog.

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Heathkit® II coupon is m issing, write Heath Co., Dept. 020-692, Benton Harbor, MI 4 90 2 2 Heath kit Pro ducts are a ls o sold and serviced at He ath ki t Electronic Cen ters (u n its of Veritechn olog y Ele ct ron ics Corporation ) in ma jor c ities th roug hou t th e U.S. See your w h ite p a g es .

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fact: fne new Shure Cartridges feature the technological breakthroughs ofthe V15JYpeIV


continued from page 78 ring feet which can be added. Altogether, the Amerex Unibox is the neat est and most convenient packaging

Plus FIG. 3

Unprecedented stylus protection

FIG. 4

system I have found for small projects. Prices are quite reasonable, also. If you can't find Uniboxes locally, write to Amerex.

the M97 Era IV Seriesphonocartridges Shure has written a new chapter in the history of affordable hi-fi by making the space -age technological breakthroughs of the incomparable V15TypeIV available in a com plete line of high-performance, moderately-priced cartridges: the M97 Era IV Series Phono Cartridges , available with five different interchangeable stylus configu rations to fit every system and every budget. The critically acclaimed V15Type IV is the cartr idge that astonished audiophiles with such vanguard features as the Dynamic Stabilizer-which sjmultaneously overcomes record-warp caused problems, provides electrostatic neutralization of the record surface, and effectively removesdust and lint from the record-and, the unique telescoped stylus assembly which results in lower effective stylus mass and dramatically improved trackabi lity. Each of these features . .. and more . . .has been incorporated in the five cartridg es in the M97 Series-there is even an M97 cartridge that offers the low di stortion Hyperelliptical stylus! What's more, every M97 cartridge features a unique lateral deflection assembly, called the SIDE-GUARD, which responds to side thrusts on the stylus by withdrawing the entire stylus shank and tip safely into the stylus housing before it can bend. NEWI M97 Series Era IV Phono cartridges . . . Five new Invitations to the new era in hi-fl.

Model M97HE M97ED


o z o a:: .....





o Ci «a::


Stylus Configuration Nude Hyperelliptical Nude Biradial (Elliptica l)


Nude Spherical


Biradia l (Elliptical)



78 rpm Stylus for all M97's

Biradial (Elliptical)

Tip Tracking Force :% to 1V2 grams 3/4 to 1V2 grams 3/4 to 1V2 grams 1Y2t03 grams 1V2 t0 3 grams 1V2t0 3 grams

Applications Highest fidelity where light tracking forces are essential. Where slightly heavier tracking forces are required. For 78 rpm reco rds.



Shure Brothers Inc " 222 Hart rey Ave" Evanston. IL 60204 In Canad a: A. C. Simmond s & Sons Limited Outside the U.S. or Ca nada write to Shure Brothers Inc" Attn: Dept. J6 for inf ormation on your local Shure di stribu tor. Manufacturers of high fid elity compo nents. micro ph ones. sound systems and related c ircuitry. CIRCLE 60 ON FREE INFORMATION CARD

The cell connection Zv i R ozensher of Briarwood, NY has in qui red about methods of connect ing parallel alkaline cells . As you know, i f one is weaker th an the others, they will discharge through that weaker one.

FIG. 5

Of course, th e usual way to prevent the di scharging is to use diodes as in Fig. 5. However, there is a voltage drop across the diodes. Zvi would like to know if any readers have found another way to connect the cells and avoid that voltage loss.

Circuit handbook I f you do any building at all , you reach a point from time to time when you need a little circuit fo r some special use. I have accum ulated a fair librar y to search through, when that happens to me. Lately, however , there is one book wh ich I turn to first. U sually, I find what I need in the new Archer Engin eer's Notebook (Radio Shack #276-5001 at $1.99) . The 128 pages of that Notebook contain much helpful information and literall y hundred s of circuits. I ncl uded are circuits th at stand alone, and others that are building blocks for larger projects. A wide variety of TTL, CMOS, and li near IC's are used. On e glance through the Notebook will convince you that it would be a very useful addition to your own library. R-E




More information on new products is available. Use the Free Information Card inside the back cover. CHART RECORDER, the IR-5207, is an X-Y recorder k it in the test-instrument line . The kit features front-pan el input filters with pushbutton controls, an int egr al paper-holdown that can be used in horiz ontal or vertical modes , and "zero" controls th at allow the pen to be placed anywhere on the chart with zero input at both coordinates.

CIRCLE 152 ON FREE INFORMATION CARD as well as cool, so the device can also be used to regulate DIP temperatures to any preset value in the range of ambient ± 60° Celsius . Price is $4.90.-Cambridge Thermionic Corp., 445 Concord Ave., Cambridge, MA 02238 .

CIRCLE 50 ON FREE INFORMATION CARD Calibrated 1, 10, 100 mV- and 1 volt -per-inch rang es are select able fro m the front panel. Other feature s are electric pen lift, calibrated X and Y sweep, and remote capability. The IR-520 7uses 8';' by 11 inch paper and two kinds of disposable pens are avail able. Price is $479.94.- Heat h Co ., Dept. 350-260, Benton Harbor, MI 49022. FUNCTION/SWEEP GENERATOR, model LFG13008, pr ovi des a wide range of capabi lities and is suitabl e for use in design, testing , and service appl ications. Housed in an all-met al enclosure, the unit cov ers frequ encie s of 0.002 to 2 MHz in 8 ranges and includes linear and logarithmic sweep mod es wit h sweep widths up to 1000:1 and sweep rate s of 0.5 to 50 Hz. Waveform outputs include

BURN-IN SOCKETS, TS-5173 , are a line of TOpattern sockets offered in both standard (150 °C with BeCu contacts) and high temperature versions (200 °C with BeNi contacts). The series is available with from 3-to-12 gold-plated contacts and features very low insertion force and a center

r-----------------------, (

) I'm so ld , send the Limiter kit , $49.94 plus postage enc losed. ( ) Send the assembled limiter $79.95 plu s postag e enc losed . ( . ) Send Free Catalog Charge Visa_M C_Card No.




Address: Cit y

_ State:_ _ Zip:


IIDIA ELECTRON ICS. Dopl. HI ,1020W.Wilsloiro.Old_a CiI,. OK 73116

~-CIRCL - - - E- 26 - -ON - -FREE - - -INFORMATION - - - - - - - -CARD - --~


CIRCLE 153 ON FREE INFORMATION CARD locating stud for greater mounting rig idity. Price is $.63 each for 1000 pieces .-Robinson-Nugent, Inc. , 800 E. 8th St., New Albany, IN 47150 . CABLE TV ADAPTOR, model 047AE, allows sub scribers to tune all cable channe ls using their TV set's remote control. The system allows reception of cable channel s through the set's UHF tuner, which can be operated remotely, thus freeing the viewer from having to get up and go to the cable


CIRCLE 151 ON FREE INFORMATION CARD sine, tr iangl e, sawtooth, and pulses . Output level is continuously vari abl e from 0 t o 20 V Pop and a push-button att enuat or pro vides up to 70 dB atte nuation in 10-dB ste ps. An auxili ary connector pro vides TTL level signals for dri ving logical cir cuit s. price is $49 5.- Lead er Instruments Corp., 380 Oser Ave., Hauppauge, NY 11787. THERMOELECTRIC COOLER, model 801-102901-00-00, is designed for use with 8, 14, 16, and 18-lead dual in-line packag es (DIP 's). When pla ced bet ween the DIP and a heat sink, it can pump out up t o 3.5 watts of heat using a modest input of DC power, th ereby allowing a DIP to operate in a hot envi ro nment. The unit can heat

CIRCLE 154 ON FREE INFORMATION CARD converter box ever ytime he wants to switch to another program. Channels 2 through 13 rem ain available through the VHF tuner. The system includes the converter, AC adaptor, 75-to-300 ohm transformer and instructions. Price is $39.95 plus shipp ing (NY residents add appropriate ta x).-ETCO Electronics Corp., North Country Shopping Center, Rte 9 N., Plattsburgh, NY 12901. R-E

Now test an amplifier or receiver's maximum power, crosstalk, distortion, and much more. The TPC-100's monitor output provides the interconnection between the amplifier and your test equipment. The TPC-100 distributes 2 channel audio signals into 4, 8, or 16 ohm dummy loads (whichare MIL grade non-inductive), or to the external speakers. To order, or for more information, contact:








testek 6910HAVENHURSTAVENUE/VANNUYS/CAliFORNIA 91406 213 786-6890


m JJ


co 00 o



continu ed from page 44 tabl et is included, enabling the user to take hundreds of readings and record th em for a variety of individuals. Th e instrument is powered by a standa rd 9-volt transistor radio battery. Because of the additional power consumption requ ired by both LED and audible indicators, use of an alkaline batt er y is recommended.

Testing the BP-1 Unpackaging the Micronta BP- l bloodpressur e test er, we found that it include d a handy vinyl carrying case, complete with contoured cut out s to support the instrument, a hinged lid, and velcro clasps. A short review of the manual was most informative. Several paragraphs are devoted to an introduction to hypertension, its causes and stat istics, and interpretation of blood pressure readings . A step-by-step procedure is out lined to fami liarize the user with the unit. Aft er reading the instructions and taking a few practice reading s, using the instru ment is a snap . T wo flexible rubber cab les from the pressure cuff are inserted into the instrument. The cu ff is placed over the upper arm, white dot located over the brachial artery. That location may be found visually by the presence of a superficial dark vein j ust to the inside of the elbow joint, palm turned up. Or , it may be detected by feeling for a pulse. With the pressur e cuff in proper position , the Velcr o wrap is snugly pressed down, holding th e cuff in place. A series of squeezes on th e bulb inflates the cuff to a pressure of about 200 millimeters. The inst rument is then switc hed on, and the release butt on is slightly depre ssed, allowing the air pressure to drop slowly until the indicat ors begin to signal. We found the cuff to be very lenient about slightly impr oper placement. Virtu ally identical readings were obt ain ed with th e white dot off center by an inch or more . But for a correct reading, the arm must be elevated to the same height as the heart (m id-chest height). Too low, and th e instru ment will show an unrea listic high reading; too high, and the instrument will show an inaccurate low readin g. Th e difference will be a significant amoun t.


your knowled

Subscribe to BYm The 1980's are here! Th e decade of the personal computer has arrived, and BYTE has made it happen! BYTE - the small systems journ al devoted to personal com puters - has helped usher in the new era. Leading the personal comp uter revolution , which is already transform ing hom e and personal life, are BYTE's 160,000 enthusiastic readers. Th eir enthusiasm has made BYTE the largest com puter magazin e in the wo rld!

Tobe knowl edgeable in the 1980's you need to know how to use personal computers. BYTE is your personal guid e to the new era. BYTE tells you how to build, buy, and use computers for fun, practical purpos es, and profit. W ith help from BYTE, you can experiment right in your own home with graphi cs, word processing, computer musi c, speech synthesizers, sim ulations, robotics, personal data base management, business com puting - and hundreds of other fascinating hardware and software applications. Resolve now to expand your computer know ledge. Subscribe to BYTE!

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To test the accuracy of the BP-l , we took our review sample to a local hospital and checked it against three resident instrumen ts. We found slight differ ence s in measurement among all instruments, but the BP- l was well within th e range of variability. A further test against a newer instrument is a dent ist 's office showed ident ical reading s. Wh ile th e ret ail cost of the BP-l is higher than most consumer-grade stethoscope sphygmoman ometer s, it appears to be of qua lity manufact ure; ours was certainly equivalent to the two-piece prof essional units with which it was comp ared . The ilnencumbered one-handed application is a distinct advantage. We find the BP-l to be both cleverly designed and realistically priced. Th e BP-l blood pressur e tester sells for $69 .95 and is available at Radio Shack stores nati onwide . R-E

~ 7890

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Write: National Committee for Prevention of Child Abuse, • Box 2866, Chicago, III. 60600


StartComputing For Just$129.95 With An 8085-Based Professional Computer Kit-

Explorer/85 100% compatible with all BOBOA and BOB5 software & developmen t tools! No matt er what you r future computing plans may be, Level " A "-at S129.95-is you r starting point. Star ting at j ust $119.95 for a L~I:~I"A" operating system, you can no w bu ild the exact computer you want. Exp lorer/aS

can be your beginner's system, DE,..f controller, or ID",{fo rmatted 8" disk small business system .. .yet you',e nt~'tr fo rced to spend a penny fo r a component or featu re yo u don '( want and you can expand in small, affordable stepsl Now, for ju st S129.95, you can own th e first level of a fully expand able comput er with professional capabiliti es-a corn puler which featu res th e ad van ced Intel 8085 cpu, thereby giving you im mediate access to all software and developmen t tools that exist for both the 8085 and its 8080A predecessor (th ey are 100 % software compatible)-a comput er which feature s onboard 5· 100 bus expansion-plus insta nt conversion to mass storage disk memor y with either 5-1/ 4" diskettes or standard IBM·f ormatted 8" disks. For just S129.95 (plus the cost o fa power supply, keyboard / terminal and RF modulator , jf you don't havethem already), Explorer/85 lets you begin computing on a significant level. .. app lying the principles discussed in leading comp uter magazines . . .develop ing "state of the art " comp uter solutions for both the indu strial and leisure enviro nment. Level "A" Specification s Explorer/ 85' s Level HA" system featur es the advanced Intel 8085 cpu, a n 8355 ROM with 2k deluxe monit or/operating system, and an 8155 ROM.l/O-a ll on a single motherboard with room for RAM/ROM /PROM /EPROM and S-IOO expa nsion, p lus generous prot otyping space. (Level "A " makes a perfect OEM controller for industrial a pplications and is nail able in a special Hex Version which .........."'..~.•~ . _ can be programm ed usin g the Nelro nics Hex Keypad / Display.) PC Board: glass epoxy, plated throug h holes with solder mask • I/O: provisions for 25·p in (DB25) con nector for terminal Level "A " at $129.95 is a serial I/O , which can also supcomplete operating system, ~~~ptro~'isi~~Pe;or t~~~Pi:e~~~ ~f;{72~: r:~~~7:::i ~~~: socket for hex keyboard /di stroller use. play.. .cassette tape record er input. .. cassette tape recorder output. . . cassette tape con trol outp ut. .. spea ker outp ut. . . LED outp ut indicator on SOD (serial output) line. .. printer interface (less drivers)... total of fou r 8-bit plus one 6-bit I/O port s · Crystal Frequency: 6.144 MHz • Co ntrol Switches: reset and user (RST 7.5) int errupt. .. additional provi sion s for RST 5.5, 6. 5 and TRA P interrupt s onboa rd • Co unter/Timer: program mable, 14·bit binary > System RAM: 256 bytes located at F800, ideal Iosmaller systems and for use as an isolated stack a rea in expanded systems . . . RAM expandab le to 64k via 5-100 bus or 4K on motherboard . Systrm Mo nitor (Ter mina l Version): 2k bytes of deluxe system monitor ROM located at FOO0leaving ll000 free for user RAM/R OM,. Featur es include tape load with labeling . . . tape dump with lab eling . . . examine/c hange contents o f memory . .. insert data . .. warm start. . . examine and change all registers... single step with register display at each break point , a debugging/t raining feat ure . .. go to execution address. . . move blocks of memory from one location to anot her. .. fill blocks of memor y with a consta nt. .. display blocks of memory ... automat ic baud rate selection variable display line lengt h control (1-255 chara cters/ line) cha nnelized I/ O monitor routine with 8-bit para llel output for high speed prinler . . . serial console in and conso le out channel so that monitor can communicate with I/ O port s. System Mon ito r (Hex Version): Tap e load with labeling . tap e dump with labeling.. .examine/ change contents of memory. .. insert data ... warm start .. .examine and change all

By Ne tronlcs

. .. go to execution address. Level " A" in (he Hex Version make s a perf ect controlle r for indu str ial appl icati on s and ca n be p rogrammed usin g the Net ro nics He x Keypad /Displa y.

Level"B" prov ide s th e 5· 100 signa ls plus bu ffer s/driver s to decoding for on board 4k RAM expa nsion select-a ble in

4k blocks. . . addr ess decoding for onboard 8k EPROM expansio n selecta ble in 8k b lock s . .. add ress and data bu s driv er s fo r onboard expa ns ion . . . wai t sta te gene ra tor (jumper selecta ble), to allow the use of slo wer memo ries ... two sepa ra te 5 volt regulators.

Level "C" Specifications Level " C" expand s Explorer' s motherboard with a card cage, allowing you to plug up to six S-IOO card s directly into the mot herboard . Both cage and Exp lo rer/Bs with L evel cards are neatly contained inside " C " card cage. Explorer's deluxe steel cabinet. Level " C" includes a sheet metal superstructure, a 5-card gold plated S· 1OO extension PC board which plugs into the motherboard . Ju st add requ ired number of S-Ioo con nector s Level "0" Specifications Level "D " provides 4k or RAM, power supply regulation , filtering decoupling compo nents and sockets to expand your Explorer/85 memory to 4k (plus the original 256 bytes located in the 8155A). The static RAM can be located anywhere from ll000 to EFFF in 4k blocks. Level "E" Specifications Level "E" add s sockets for 8k of EPROM to use the popular Inte l 2716 or the Tl 2516. It includes all sockets, power supply regulator, heat sink, filtering and decoupling components. Sockets may also be used for soon to be available RAM IC' s (allowing for up to 12k of onboa rd RAM). Order A CoordInated Explorer/a5 Applications Pak! Experimenter's Pak (SAVE SI2.50 )-Buy Level "A'· an d Hex Keypad/ Display for 5199.90 and get FREE Intel 8085 user's manua l plus FREE postage & handli ng! Sludent Pak (SAVE 524.45)-Buy Level " A, " ASClI Keyboard / Comput er Terminal, and Po wer Supply for 5319.85 and get FREE RF Modu lator plus FREE Intel 8085 user' s manu al plus FREE postage & hand ling! Engineering Pak (SA VE 541.00)-Buy Levels "A ," · ' B," "C,' · "D,' · and " E·' with Powe r Supply, ASClI Keyboard/ Comp uter Terminal, a nd six 5-100 Bus Con necto rs for 5514.15 a nd get 10 FREE compute r grade cassette tape s plus FREE 8085 user's manu al plus FREE postage & handling! Business Pak (SAVE 589.95)-Buy Explorer/85 Levels " A," " B," and "C" (with cabinet), Power Supply, ASCII Keyboard/ Computer Terminal (with cabinet) , 16k RAM, )2" Video Monitor, North Star 5-1/4" Disk Drive (includes North Star BASIC) with power supply and cabinet, all for just 51599.40 and get 10 FREE 5-1/4 " rninid iskettes (S49.95 value) plus FREE 8085 user' s man ual plus FREE postage & handling!

CALL TOLL FREE 800-243-7428


Special Computer Gra de C~lte Tapes, 51.90 each or 3 for 55, postpaid . 0 12'" Video Monitor (10 MH z bandWIdth), 5139.95 plus S5 p&h. D . Nort~ Sta r Dou~le Density Floppy Disk Kit (One Drive) for Explorer/ 85 (includes 3 drive S-IOO controller, DOS, and extended BASIC with per-


sonalized disk operati ng system- just plug it in and you' re up and runn ing!), 5699.95 plus S5 p&h . O Power Supply Kit for North Star l Disk Drive, 539.95 plus S2 p&h. 0 Deluxe Case for Nort h Sta r Disk Drive, 539.95 plus S2 p&h. 0 Experimenter's Pak (see above),1 5199.90 postpa id. 0 Student Pak (see above), 5319.85 postpaid . 0 Engi neeri ng P ak (see above) , 5514.75 postpaid. O · Business Pak (see above), 51599.40 postpaid .


I I I I Tota l Enclosed S (Conn . res. add sales tax) ByI 0 Personal Check o M.O.lCashier's Check 0 Visa 0 Master Char ge I (Bank N- - - - ) Acct . N Signature Print Name

I Exp. Date --I

Address . City


. State 0 Send Me ZipInfor mation _ _ •


The Netronics ASClI/BA UDOT Computer Terminal Kit is a microp rocessor-contro lled, stand alo ne keyboard /terminal requring no comp uter memory or softwa re. It allows the use of either a 64. or 32 character by 16 line professional display format with selectable ba ud rate, RS232-C or 20 rna. ou tput, full cursor contro l and 75 ohm composite video output. The keyboard follows the sta ndard typewriter configuratio n and generates the entire 128 character ASCII uppe r/lower case set with 96 printabl e chara cters. Features include onboard regulators, selectable parit y, shift lock key, alpha lock ju mper, a drive capab ility of one TTY load, and the ability to mate directly with almost any computer, including the new Explorer/85 and ELF products by Net ro nics, . The Computer Termina l requ ires no I/O mapping and Includes I k of memory, characte r generator, 2 key rollover , processor controlled cursor control, parallel ASCII/BAUDOT to serial conversion and serial to video processing-fully crystal contro lled for superb accuracy. PC boa rds are the highest quality glass epoxy for the ultimate in relia bility and long life.

VIDEO DtSPLAY SPECIFICATIONS The heart of the Netronic s Computer Terminal is the microprocessor-controll ed Netroni cs Video Display Board (VID) which allows the terminal to utilize either a parall el ASC II or BAUDOT signal source. The VID converts the para llel data to serial data which is then formatt ed to either RS232·C or 20 rna . current loop output, which can be connected to the serial I/O on your computer or other interface, i.e., Modem. When connected to a computer , the computer must echo th e characte r received. This data is received by the VID which processes the info rmat ion, converting to da ta to video suitable to be displayed on a TV se'l Xusing a n RF modulator) or on a video monito r. The VID generates the cursor horizo nta l and vertical sync pulses and perfor ms the ho use keepin g relat ive to which character and where it is to be displayed on the screen. Video Output: 1.5 PI P into 75 ohm [ElA RS-170j . Baud Rate: 110 and 300 ASCII · Out puts: RS232-C or 20 maocurrent loop • ASC II Character Set: 128 printable characters-

BAUDOT Charac ter Set: A B C DE FG H I J K LM N P Q RS TU V WXYZ- ? : ·3$ N{) . , 90 14 !5 7;2 /68 . Cursor Modes: H ome, Back space, Hor izonta l Tab, L ine Feed, Vertical Tab, Carriage Ret urn. T wo special cursor seque nces are prov ided fo r absolute and relative X- Y cursor addressing . Cursor Control: Erase, End of L ine, Erase of Screen, Form ~er:::iaf::lete • Monit or Opera tion: SO or 60H z (jumper Continental U.S.A. Credit CardBuyers Outside Connecticut

CALL TOLL FREE 800-243-7428

Continental U.S.A. CreditCard Buyers Outside Connecticut

ToOrder From Connecticut Or ForTechnical Ass istance . Etc. Call (203)354-9375


Terminal $14995

suppo rt up to six 5-100 bus hoard s and includes: addre ss

0 Deluxe Steel Cabinet for ASC II Keyboard/ Terminal, S19.95 plus S2.50 p&h. 0 Power Supply Kit( ± 8V @ 5 amps) in deluxe steel cabinet, 539.95 plus S2 p&h. 0 Gold Plated S-IOO Bus Connec tors 54.85 each. postpaid . ' 0 RF Modul ator Kit (allows you to use your TV set as a monito r), 58.95 postpaid . 0 16k RA M Kit (S-IOO Board expands to 64k), 5199.95 plus S2 p&h. 0 32k RAM Kit, 5329.95 plus S2 p&h . 0 48K RAM Kit 5459.95 plus S2 p&h 0 64k RAM KitM89 95 plus S2 p&h . 0 16k RAM Expa nsi~n Kit (to expand any o f th e above up to 64k), 5139.95 plusS2p&h each. 0 Intel 8035 cpu User's Manual, 57.50 postpaid .


Compu t er

Hex Keypad/Display Specifications Calculator type keypad with 24 system defined and 16 user defin ed keys. 6 digit calculator type display which displays full address plus data as well as Hex Keypad /Display . registe r and stat us in format ion . Level "B" Specifications

N etronic8 R &D Ltd., Dept. RE-9 ~333 -Litchfield - - -Road - -New-Milford, - -plusCT -S2 p&h. - --06n6 Please send the items chec"iM below -

o Explorer /85 Level "A" Kit (ASClI Version), 5129.95 plus S3 p&h. o Explore r/ 85 Level "A " Kit (Hex Version), $129.95 plus S3 p&h. o 8k Microsof t BASIC on cassette tape, $64.95 postpaid . o 8k Microsoft BASIC in ROM Kit (requires Levels "B," " D,'" and " E'" ), 599.95 plus S2 p&h. o Level '· B'" (S· IOO) Kit. 549.95 plus S2 p&h. o Level "c" (S-IOO 6-<ard expander) Kit, 539.95 plus 52 p&h. oI Level "D'" (4k RAM) Kit, 569.95 S2 p&h pus . o Ln,1 "E'" (EPROM /ROM) Kit, $5.95 plus 50¢ p&h. . o Deluxe Steel Cabinet for Explorer/ 85,549 .95 plusS3 p&h. O. ASC~I Keyboard/Computer Termlnal Kit (featu res a full J28 character set, upper & lower case, full cursor control, 75 ohm video output convertible to baudot output selecta ble baud rate RS232-C or 20 m~. I/O , 32 or 64 char: acter by 16 line formats, and can be used with either a CRT mon itor or a TV set (if you ha ve an RF modu lator) 5149.95 plu s S2.50 p&h. ' I .i:J Hex Keypad/Dis play Kit, 569.95 .


register s .. . single step wit h registe r di spla y at each br eak. po in t

_ ..

To Order From Connecticut Or For Tec hnical _ Ass istance , Etc. Call (203)354-9375


Netronics R&D Ltd ., Dept. RE-9 333 Litchfi eld Road , New Milford, CT 06776 Please send the items checked belowo Netro nics Sta nd Alone ASCII Keyboa rd/Co mputer Tenn inal Kit, 5149.95 plus S3.00 postage & handling. o Deluxe Steel Cabinet for Netronics Keyboa rd/ Terminal In Blue/ Black Finish. 519.95 plus S2.50 postage and hand ling. Video Display Board Kit alone (less keyboa rd), 589.95 plus S3 postage & handlin g. o 12" Video Monitor (10 MHz band width) fully assembled and tested , 5139.95 plus S5 postage and handling. o RF Modulato r Kif (to use your TV set for a monitor) , 58.95 postpaid . 5 amp P ower Supply Kit In Deluxe Steel Cabinet ( ± 8VDC @ 5 amps, plus 6-8 VAC). 539.95 plus S2 postage & hand ling. Total Enclosed (Conn . res. add sales tax) S _ Byo Personal Check 0 Cashiers Check/Money O rder Visa 0 Master Charge (Bank N )




Acct . N

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.JE e:xp. Date

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City • Stale .. _ _




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s:OJ m







~I Transceivers with all the op eratin g contro ls built into the microphone HERB FRIEDMAN, COMMUN ICATIONS EDITOR STARTING WAY BACK IN TH E DARK AGES

of CB when all transceivers used vacuum tubes, many attempts have been made to plac e cha nnel selectio n and other frequentl y used fun ct ions, suc h as volume a nd sq uelch co ntro l. in the microph one. (Among other be nefits it allows a vehic le's dri ver to change channels without leanin g across the seat. and/or tak ing his eyes off the road .) Som e ea rly " remote contro l" des igns had RF run ning all over the place, and the y made the "Rube Go ldberg" co ntr apti on s we used to see in the Sunday comics look like adva nced engineeri ng by comp ar ison. Successful full-feature remote control from the microphone didn't come about until Large-Scale Integ ration-s-or LSI as it is mor e co mmo nly te rmed-was used for phase-locke d osc illators and their co ntro l circuits.

FIG. 1

FIG. 2

The phase -locke d oscillator generates both the receiver's local osc illato r freque ncies and the frequencies from which the trans mitter's outp ut freq uencies are deri ved. Not very long ago

th at was a formidab le design with a cost a nd co mplexity that limited its use almos t exclusively to radio astro nomers. But by substituting solid-sta te de vices for vacuum tub es , and then using LSI as a substitute for hundred s of discrete components , almos t ove rnight the pha se-locked detect or beca me an Ie no larger than your inde x finger. It was pric ed well und er $ 10 in manufacturing qu anti ties . (Actu ally pennie s in tod ay' s marketplace .) Today, we have Large Sca le Integra; tion of Large Sca le Integration . That's about the ony way to describe shrinking a de vice the size of your index finger to so mething slightly smaller than half the length of your little finger. Eve rything has become so small it's now possible to build virtually aUtran sceive r co ntrols, including channel se lec tion, into th e microphone itself, ju st as Cobra has done in their model 66GTL remote (Hideaway) 40-Channel cont inued on page 92



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Test Equipment Digital Scope Muni· plexer-to con vert almost any scope into a 4-trace unit. Frequency M ulti· pller-to extend the range of your frequency counter. Safety Cooker-that protects unattended equipment against electrical problems. Battery Box/ Switching Boxa great accessory fo r any bench . Car Test Probeuse it to test auto-

motive electrical systems. DigitallC Testerto make quick work of testing digitallC's. Electronic Music The Chord Egg-to generate an endless series of chords automatically. Words And Musica programmable music generator that's ideal for doorbe lls. Big So und For Chord Organs- to enhanc e the sound

from electromechanical chord orga ns. Comput rs Digital Logic Trainer-that teaches how microprocessors work. save Your Filescassette tape recorder controller makes using tape as computer memory storage easy. Programmable Sound Generatoradds sound capability to almost any com puter system.

Hobby Adventures of the IC's-applications for LM3914and VMOS

power FEr's. Digital Do ·Nothing Box-lights, counts, teaches binary and digital number systems. Communications Digital Readout Add-on For Communications Receivers-to update older receivers easily. M icrophone Acous· tic Coupler-a slm-

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CB mo bile radio . And it is do ne at very little extra cos t to the co nsumer beca use of LSI. Figure I shows the co mp lete Cobra package co nsisting of the hideaway m ain uni t. that ca n be concealed eas ily und er the dash boar d or under the sea t. a nd the plug-in micr ophone that contains a co mbinatio n speaker/microphone a nd all operating co ntro ls. They include the cha nne l selec to r. volume. and sq uelch co ntrol s. AN L on-off switch. RF gain-co ntro l switch. instan t cha nnel<) selecto r switch. and push-to-talk switch. A two-di git LE D indicator is the cha nne l display. T he inside of the mike is shown in Fig. 2. He re we see how the magic is acco mp lished . T he speaker . removed from the ca se so you ca n see all of the inte rio r. also serves as the microp hone. In add itio n to the miniature co ntro ls a nd switc he s along both edge s of the microphon e . ther e is a single LS I IC in the ce nter. T hat IC is the key to full remo te co ntro l operation. The IC serves as bot h the driver for the LED ch annel indicator and the con tro l fo r the phase-locked oscilla tor that is locat ed in the main unit- no RF flows hack and forth betwee n the microphone a nd the m ain unit. Each time the channel selector is pu shed. up o r dow n to s te p th e cha nnel se lec tor one channel at a time. the IC cha nges the LED disp lay one channe l (up or down) . It also sends a co ded DC signa l to the phase-locked oscillato r. that ge nerates the ope rati ng frequ en cies co rres pondi ng to the indica te d cha nne l se lection. T he insta nt c ha nne l-9 switch. ove rrides the normal c han ne l se lectio n and force s the IC to tr a ns mit the proper DC co ntrol signals needed by the oscillat or for cha nnel-9 o pera tio n. Simulta neou sly. the IC c hanges the LED displa y to indicate a " 9." T he micr oph on e schematic is shown in Fig. 3. IC pins num ber ed 7 th rough 12 provide the co ntrol signa l to the osc illator in the main unit. Ju st about eve ry t hing e lse is se lf-ex pla na to ry. Simp le? Ye s? Low cost ? Again. yes. Was this po ssible four or five years ago? No t with only two IC ' s in a mod erat el y priced package it was n' t. T he technology exi sted: but without LS I and th e co st redu ction inhere nt in the mult i-million do llar CB marketplace yo u' d probably still be readi ng a bout .. Futu re a pplications of the phase locked osc illator. " rat her than holding it in th e pa lm of your hand .


6 o« c: 92

Temperature compensation in a frequency counter


sa te d C ry sta l Oscillat or. To anyo ne even rem ot ely involved with communica tions equ ipment it co njures up a vision o f a crys tal wra pped in a thermostat ically co ntrolled heating element to main tain the cry sta l tem perature within ve ry narrow limits to reduce , or eliminat e , freq uency dr ift. Virtually all broadcas t a nd non- CB commercial co mmunications tra nsmitte rs (and some rece ivers) ha ve a TCXO somew here in th e freq ue nc y generating or co ntro l ch ain . Most certa inly, every lab-grade frequency co unte r and/or meter has a T C XO, and eve n an F. C.C.- approved frequenc y counte r (for tran smitt er freq uen cy te sts) has a TCXO. No w th ere ' s a han d-h eld 8-digit 50 to 500-MH z frequenc y co unter that sells for only $ 169.95 co mplete with a rech ar geabl e batt ery pack and charger. It e ven ha s a telescopic antenna that can se nse signa ls from hand -held walkietalki es. Featuring OA-inch LE D readou ts, the unit, the model 500HH from OSI Instrument s , also feat ures a I-PPM TC XO. Si nce th e unit is batt ery-powered , a logical qu estion is: "How is the TCXO he at er powered'?" Actua lly. there ' s no heat er. Nothing in TCXO mean s that th ere is a heater : it' s simply been assumed that there was , becau se TCXO's alwa ys used a heat er for temperature stabili za tion , What OSI has done is to de sign their oscillato r so it is within I-PPM over a relati vel y narrow temperatu re range of 17° to 40°C, or 62.6° to 104°F . Ju st great for indoo r use ; but no I PPM is guara nteed w he n wo rk ing on a vehicle or bo at out in the co ld. or in the hot sun. In a sense, the 500HH is temperat urecompensat ed for indoor use , but ca lling it TCXO is an unfortunate choic e of words for a device that doesn 't ha ve a heat ed crysta l. Unfo rtu nate, because the 500HH is an exce llent dev ice, well worth th e mone y ; yet man y tech s are o bv iously go ing to qu estion the use of " TCXO" to describe an oscillator with a n unhe at ed cry stal. Th e 500HH has two BNC inputs : one for the d irect 50-M Hz counter ; the othe r thro ugh a x 10 prescaler that pro vide s a SOD-MHz inp ut. A switch selects eithe r input. A second switch pro vides power off in the ce nte r position and a time base of O. I sec for MHz. and I sec fo r kHz. Th e switch automatically co rrects the deci ma l point. To conser ve th e battery , because LE D' s eat up a lot of c urre nt. all leadin g ze roes are suppr essed . In ac tu al fie ld te sts-i ndoors of co urse- the OSI model 500HH was within 10 Hz of a n F.C. C.-approved freque nc y cou nte r' s reading at approx imat ely 100 MHz . T ha t' s abo ut as good a n acc uracy as yo u' ll ever need for indoor frequ enc y measuremen ts when tro ublesh oo ting eq uipment.

FIG. 4

T he unit mea su res approx imately 3- 1/2" wide x 5-7/8" long x 1-3/16" thick ; a nice size for a toolbox. The BNC co nnect o rs a nd sw itches are along the top edge . Th e c ha rge r/ AC power co nnector is o n the rear. as is an access hole to the

crysta l' s trimmer ca pacitor. You can take a loo k at the ins ide of the co unter in Fig. 4. Ove rall it' s a very co nve nient and inex pensive frequ en cy meter for the tec h or hobb yist on a tight budget. It' s simply unfort unate that the temperature range isn 't clearly spelled out in OF . a more comm on reference than °C (at least in thi s co untry). a nd all mention of a non-heated TC XO should be eliminated ; the inst rumen t is simply too goo d for that kind of weasel-wording. Additiona l inform ation on the model 500HH is available from DSI Instrumen ts , Inc .. 7924 Ron son Rd.. Sa n R-E Diego . C A 92 1I I.

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Typical problems with tripler circuits and some not so typical. JACK DARR , SERVICE EDITOR A GREAT MANY SOLI D-STATE TV SETS USE

voltage multipli ers to develop the high voltage for th e picture tube . We call th ose trip lers, although some of them are actu ally quadruplers. In any case, from now on we'll call the device a " tripler" to save space. The symptoms and reacti ons are th e same with both . The units are all encapsulated and, as a rule, quite expensive; so we need tests that will identify tr oubles th at are in the tripl er. As with everyt hing else in this business, including picture tubes, we can find symptoms th at apparently point to th e troubl e only to find after replacing the suspect componen t that the symptoms are still there. Th at can be definitely non-habit -forming because it's time-wasting and expensive. Th e main symptom of a bad tripler is very low or no high voltage at all; some may short int ernall y. For eit her case, the best test I know of is to unh ook the input lead from flyback to tripi er , and recheck. If all of the other voltages derived from th e flyback are norm al (the boost and low DC voltages for exampl e) and ther e's no sign of overload, th at is pretty conclusive. Not definite yet, though! There are often other th ings that can cause those symptoms. One is the bleeder resistor used in many sets to develop the focus voltage. That will be tied dir ectly across the high-voltage output of the tripl er. If the bleeder should be internally shorted or arcing, that will load down th e high-voltage supply and fake a bad tripler. To test th e bleeder resistor, first disconnect it and then recheck for high volt-

age . In one odd case recentl y, in the Clinic mail, the symptoms were a " frying sound" -with hash on the screen and interference in nearby AM radios . Tha t turned out to be int erna l arci ng in the focus bleeder. The high voltage shutdown circuit may be fed from a tap on the focus-voltagedropping network; below the main large resistor. However, if there is a problem here , the flyback will not develop the boost and other DC voltages. Another circuit that causes symptoms often blamed on tripl ers is the ABL (Autom atic Brightness Limit er). Th at is sometimes fed from a special tap on the tr ipler. Key clue here-if th e high voltage is up to norm al, then the A BL is cutting the raster off. Figur e I shows a typical circuit using a dua l sense-voltage for the high-voltage shutdown, and an ABL as well. That is used in the Magna vox T9 89 chassis. Some other sets may use one or both of those or a minor variation . However, the y all do t he same things . By the way, in all sets, watch out for "run changes!" Some chassis may not have the circuitry shown on t he schematic you have. For example, the early run of the T989 didn't use Q303, the high-voltage protection transistor; it is used in later ru ns. (It's on the mother board ju st in front of the flyback panel.) Both of the circu its shown do the same thing : tr ip the SCR shutdown to kill the drive to the horizontal-output stage. The circuit on th e " D" panel senses high voltage, while Q303 senses beam current. 390n

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Magnavox recommends that when a tripler has failed you should check the A BL stage and the LL V ( Low-Level Video) board for possible damage to the ABL circuit from transients produced when th e tripler went out. Tripier arcing isn't always "terminal." My friend Leon Caldwell has found some triplers in Philco and Sylvania sets that have arced thr ough the bottom of t he case, thr ough the encapsulant. Lift the case away from ground, and the unit works fine. He cleaned all of the carbon off the bott om, th en plastered it with silicone rubber sealant. The case was set up on insulatin g blocks, and the space below it filled with that sealant. Worked perfectly-no callbacks. I've also heard that Zeni th is sending out, together with each tri pler sold, small tubes of that type of sealant. It's used to cover all of the tripl er term inals to prevent corona or arcover. In another Magnavox, Leon found what seemed to be high-voltage trouble ; raste r gradually dark ened and went out. Checking, he found that by pushing the VIDEOMATI C button and adju sting the preset controls, th e raster came back! Th at was suspected when the high voltage was found to be up with a dark raster. Cleaning the switch was all it took to fix it up. An odd case showed up in a Sylvania CX4146W . After repairs to the vertical cir cuits, retr ace lines showed up in the rast er . N ot really object ionable, but visible. Two days after the set was sent home , the owner reported a loud snapping noise. That was due to arcing from the tripier, which had burnt a hole in the case. After it was replaced, the set worked fine and th e retr ace lines were gone. Th e technician who sent that in didn't have an explanation, and neith er do I-but it happened. Incidentally, th ere have been other cases with simi lar sym pto ms which turned out to be a bad electrolytic filter capacitor in the automatic brightn ess limiter circuit; on the sense-voltage line from th e trip ler. Check for that possibilit y if you run into that problem. So: if you suspect tripler trouble, make th e test s given, to make sure that it is actually th e tripier, and not some of the other circuits. As usual, there are a number of thin gs that can fake you out, so be sure to be on the lookout for them! Good R-E luck! Serv ice Questions on page 98




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continued from page 96

service questions HOT SCREEN RESISTOR I've got an odd problem. The damper tube in this J.C . Penney 4849A got red hot and burned out. While making voltage checks with it out, R904, 220 ohms got very hot. (Note: That is the horizontal output tube screen resistor.) What is the cause?-V.F., Nebraska City, NE.

Cr ystal ball says that damper tube could have shorted internally; or, the 6GK6 horizontal output tube is shorted. The hot resistor in the screen is normal! If you pull the damper tube, you have no plate voltage on the outp ut tube. The screen grid, being the only element supplied with voltage, th inks it's the plate and tries to conduct all th e current. In some sets, I've seen that tube looking like a toaster! The screen grid gets red hot! Current meter in cathode of 6GK6 will tell you whet her that stage is taking too much current. With the damper tu be out , all current in that stage must flow through the 6GK6 cathode. ROLL CHARTS FOR TUBE TESTERS On a question as to availability of new roll-charts for tube testers, I replied, truthfully, that I'd been looking for years and never located a reliable source. John E. Johnson of Thomasville, GA , comes back with this litt le jewel: Coletronics Service Inc ., 1744 Rocka way Ave., H ewlett, NY 11557, has new charts for Precision Tube-Master Series 10-12, for $8.95 plus 50¢ shipping. The Hickok Electrical Instrument Co. advised him that for charts for an old TV -7 B/U, to contact: U.S. Navy Supplies, 5801 Tabor Ave., Philadelphia, PA 19120. We pass that along for anyone who might have one of these instruments. Thanks, John .


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I'm having a focus problem with an RCA CTC-22. The damper diode was shorted. Changing that restored high voltage but not focus.-L.N., Philadelphia, PA.

Toshib a C-095 had a peculiar rast er distortion. The upper left hand corner was expand ed diagonally. Blooming was present in that area, too. Not due to highvoltage regu lation, either. "You suggested checking for feedback. In a way, that' s what it was! A 100 !J.F capacitor in the pincu shion stage apparently had a high power factor. It checked OK on an ohmmeter. A capacitor tester showed it as less than 50 !J.F. Replacing that fixed it. "Last quest ion: Years ago, the y told us that tr ansistors would do away with int ermittents. Wh en are th ey going to start making those perfect devices?" Thanks, AI. To your last question, I've been wondering for many years! HOT RESISTOR In this GE 25MB chassis, the breaker tripped. I pulled the high- voltage module and that cleared it up . A new module didn't help. Resistor R1318 was high and showed signs of heating. I changed it and the new one overheats. All other modules were checked. What's going on here?C.C., Amityville, NI.

Resist or R 1318 is a series resistor in what seems to be a crowbar circuit in the high-voltage regulator module . It 's connected from the + 170V line through Q 1304, an SCR, to ground. The SCR gate is triggered by sensing the + 150volt regulated DC output. That circuit uses a series Zener diode, and a couple of others. Check the SCR and if it's not shorted , check the trigger diode and others. Something seems to be firing the SCR! WIGGLE IN SETUP LINE This Sylvania D-12 had several wrinkles in the left end of the setup lines in with the service switch in the service position. Couldn't think of any reason for it. You suggested it might be something in the deflection yoke. This was a new Thordarson . Turned out th at it had a 680 pF capacitor on the top half of the horizontal winding . Repl acing that wit h 100 pF correct ed the wiggle and the other prob lems. Th anks for the aid. William J . Sh inn, New Carlisl e, OH . Thanks to you Mr. Shinn! Definite feedback from the field is a hug e help to everyone . GASSY TUBE?

I suggest checking all the loads, etc. Sin ce th e focus voltage in that chassis comes from th e boost voltage, check all of the capacitors around the hori zontal efficiency coil and the coil itself. (Feedback: " I tried those things. The horizontal efficiency coil was shor ted! Th anks!")

I replaced the horizontal output and damper tube in this Zenith 12B14C50. Works beautifully. However after about 15 minutes of operation, I see little blue flashes around the bottom of the horizontal output tube. Tried a new one and got same th ing. Is that tube gassy?-R.O., Daly City, CA.

ODD RASTER DISTORTION Al Yarborough of Yarborough Electr onics, Lexington , NC, sends this along: "Here' s field feedback for you. This

This is a very old problem showing up in a new set! There are two things that can cause "blue glow" inside of tubes with high voltages applied. One, of course, is "gas ," meaning just a wee bit or

air leakag e. Th e typical symptom of that is a soft cloudy blu e glow but looking close ly, you'll see that it is inside t he plate cylinder or rectangle. A similar thing that 's fooled lots of us is really quite different. C heck' your tub e; see if those blue flashes are actua lly on the inside wall of th e bulb! See if it flickers too. Th at is ju st the opposite of gas: It 's called fluorescence and is du e to a wee bit of th e gette r material on the walls. That lights up under a high voltage field, means a very hard vacuum! ODD PROBLEMS First th ing on this Zenith 19CC19 was no red. Changed the IC demodulator and fixed that. Now I've got a weird symptom: good picture in the center of the screen but both sides are bowed in; that area is blank. Controls all work. What is it?-J. V., Punxsutawney, PA.

It sounds to me that you' re gett ing some 60- Hz sinewave blanking into the video. Ju st for luck, scope the DC power supplies, especially th e + 25 and + 34 volt outp uts. I see that th e + 25 volts come directl y from th e vertical centering control and the B + . Th ere would normally be a 60-H z pulse here and it should be filtered out by t he 500-Il F electrolytic on this line. Check that one. LOW VOLTAGES AND VERTICAL PROBLEMS In this 16M91 Philco, several of the voltages are low and the boost voltage fluctuates quite a lot. Can't get a setup line with the service switch in the service position. Ver tical linearity control arcs, too. What are all those?-C.G., Derry, NH.

Easy one first: If your boost voltage is low, chances are your pict ure t ube screens are, too. Th at could be why no setup lines. Replace that vertical linearity control if it' s arcing int ern ally. For the rest of the pro blems, that could be something that is com mon to the whole circuit! In ot her words, one of th e filter capacit ors. (From lookin g at th e schematic, it is susp iciously like my own old CTC - I5 RCA! So, if I say "filter capacit ors" , I know whereof I speak . I've been there. Check all of th ose ground points on th e PC board , too.) Feed back: It was th e electrolytic capacitor on the + 275-volt line! Bingo. LOW-VOLTAGE PROBLEM There are no low voltages from the flyback in this Sears 528. 42000400. No +27.2 volts DC or +28.8 volts at all. The diode, D504, seems to be good. I see a high pulse on the flyback side (anode) but none on the cathode, and no DC voltage. The high-voltage, boost, etc., are very close to normal. Thanks for any help.-G.P., Silver Spring, MD .

You sho uld see pulses on the anode of D504 , but you should not see any at all on the cat hode . Th ere (s a 1,000 IlF capac itor to ground here! From your symptoms, the

only th ing I can see is an open diode! If the pulse is present and no DC voltage is developed, the diodes may be open, or th e 1,000 IlF capacitor shorted. Your flyback pulse output seems to be nor mal, since all of the othe r voltages are in the ballpark. Be sure to use a fast-recover y type diode for D504 . Ord inar y sinewave types won't last more than 30 seconds!


A DISC O-PICTURE T his J .e. Penney model 2868 came in wit h an odd sy mptom. Th e pictu re bright ness varied like a strobe light in a disco. Also, no color and a small raster. Sc oping the DC supply showed a sawtooth of almost 80 volts! After qui te a bit of checki ng, C807 was found open. (No te : Th at is a 1.0 Il F capac itor, on the base of clipper TR 802, from the collector of the sawtooth genera tor TR80 I. Part of saw-forming network, on the regulator board.) Th at caused t he regulator to hunt, and almost go into oscillation. Replacing it cleared up the problem . Th anks to Dean Car penter, N 5A FT, in Garland, T X, for that helpful hint.



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PIEZOELECTRIC co ntinue »! F OIII pug« 60

L E D' s can be c hec ked easily us ing th e CON T I NU ITY mode of th e tester bec au se th e L ED wi ll glow whe n pro pe rly co nnec te d (co rrec t pol a rity) . W he n the test le ad s to th e LE D a re re versed. th ere w ill be no so und because the LED is op en in that d irec tion . In th e sa me mann er, you ca n test infrared OR) LED' s even though yo u ca nnot se e th e IR LE D glow . If yo u get a so und in both di re cti on s. th e LE D is shorte d (th e sa me as fo r a sho rted d iod e ). So und in one dir ection sho ws th at the L ED o r d iode is co nd uc ting in th e fo rwa rd d irection (front-to-buck) a nd no so und in th e o ppo s ite directi on (no conduction) sho ws that the back-to-fro nt ratio is good . Voltage Tester- Vo ltage-leve l tests ca n be mad e by using the piezoel ectric so unde r in its bas ic mod e . where I to 20 vo lts DC is a pplied to its termina ls . It can be used safe ly in tra nsis to r a nd TIL c irc uits. a uto mobile troub le- sh o oting, c hecki ng th e ge ne ra l co nd itio n of ba tte ries , includ ing wa tc h a nd ca lc ulato r batt eries, because of its lo w c urr e nt drain . It is hand y for te sting in a ny circuit where yo u wa nt a ge ne ra l indi cat ion of co rrec t ci rc uit ac tiv ity and w he re you use th e ea r instead of the e ye to te ll yo u th is co nd ition. Piezoelec tric sounder and aud io alert ing devices are mo re and more co ming into o ur lives adv ising us of co ndition s in th e e nv iron me nt surro undi ng us. Ma y the y a lways bee p o r so und in yo ur fav or! R-E







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. nyone man.ges to s tart your car G.rd-A-C. r s t. lis tha engine " dead ". The thi.f can 't restcrett I nd must fl •• or be caught! A li med circuit br . aker In t he unit cut s th e po wer. The contro l bo x is oper.ted by flippin g th e switc h " on" wh en you lel ye th e ear and " of f " w hen you return . Easil y h idd en w hereyer you want - no ho les to drill · on ly 2 wtr es to connec t. Ther . is no int ert erence with norm,l car operatton. Design ed for . ny igniti on . yl tem. An d there' s mer e! Whe n you se nd in your ord er with t he cou pon below you save $2.00 off our regul ar catalog price of $21.95 and yo u will also recel ...e a free copy of our nati on ally famous 68-page t ull color sec urity system catalog wi t h o...e r 1,400 it .m s! !

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Name Address

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More information on stereo products is available. Use the Free Information Card inside the back cover.


AM/FM RECEIVER, model R6, is one of a line of new receivers that feature quartz-locked tun ing with digital readout for precise RF reception and a four -function fluorescent metering system. This system gives an accurate readout of AM signal stre ngth, FM signal strength, mu lti path, and pow-

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TRUL Y "HUMAN ENGINEERED" AND ERROR PROOF RS-200 R-box: 111 to9.999.999U; 1%0.5watt. ONLY $89.85 RS-201 : 0.1 %. $179.95 CS-300 C-box: 100pF to 99.9999 /I F; 4%. 100 volts. ON LY $99.95 CS-301 : 1%. $198.95 RCS-500 RC-box: Combination unit ONLY $185.95 RCS-502: Combines RS-201 & CS-301 . $369.95

Simply dial the desired impedance or RC value on color coded switches an d use.



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CIRCLE 133 ON FREE INFORMATION CARD CIRCLE 131 ON FREE INFORMATION CARD er outp ut. Other featu res are a low-noise circuit for increased stability with low d istortion, a high speed amp lif ier sect ion, and external jacks fo r signa l or tape accessories. Model R6produces 60 watts-per-channel into 8 ohms, from 20 Hz to 20,000 Hz with 0.05% THO. Suggested retail price is $650.-SAE, Inc., 701 E. Macy St., Los Ange les, CA 90012 . SPEAKERS, Mitsubishi model MS -20 and mo del MS - 10, are two-way acoustic air-suspension units that use a unique honeycomb tec hno logy in the woofer. The woofers are built of rig id, light weight aluminum honeycomb material covered with glass-reinforced plastic, thereby reduc ing distortion caused by unwanted vibration . The system improves lOW-frequency performance and the airt ight seal made from the honeycomb materia l improves air -suspension performance.

user places a record on the turntab le, closes t he lid to seal it, and presses the start button . The t urntable then takes over, determining sty lus contact points and t he begi nning and end of play. With a gimbal suspe nsion and a dynamically balanced tracking arm, t he unit can be used in the normal flat position or can be stood up right dur ing record play. A core less DC motor drives the arm and an optical sensor near stylus tip determines ope ration. Car battery or any 12V DC pow er sup ply can be used, as well as standard AC. Price is $600 . -Technics, One Panason ic Way, Seca ucus, NJ 07094. AMPLIFIERS, Model KAC -80 1and KAC-727, are two high-power amplifiers designed for car stereo systems. Model KAC-801 (shown) delivers 50 watts-per-channel into 4 ohms over a range of 20 to 60,000 Hz at 1% total harmo nic distortion. Other specifications include a signa l-to -noise ratio of 80 dB and a frequency response of 20 to 70,000 Hz. The unit has a bu ilt -in DC/DC converter to create the high vo ltage required to supp ly t he output stages and has an electronic fault-protec tion circuit to prevent wiring shorts or overloads. Measuring 11'1, X 2'1. X 6"1" inc hes, the amplifier is designed for trunk installation but can also mount under a car seat.

CIRCLE 132 ON FREE INFORMATION CARD Other features are over load protection circuits and tweeter st ructures that reduce reverberation. The MS-20 (shown) can handle power up to 120 watts; MS-10 up to 100 watts. Model MS-20 weighs 40 Ibs. and measures 14'1, X 24'1. X 11'1, inches. Suggested reta il price is $250 . Model MS10 weighs 32 lbs ., and measures 12'1, X 22 '1, X 11';' inches. Suggested retail price is $ 165.Melco Sales, Inc., 3030 E. Victoria St. , Compton , CA 90221 . COMPACT DIRECT -DRIVE TURNTABLE, model SL-10, is a compact quartz unit measuring t he same as an LP record jacket. Everything is auto matic and the upper and lower halves of the cab inet are sealed dur ing play . To use the SL -10 , the

CIRCLE 134 ON FREE INFORMATI ON CARD The model KAC-727 is an under-dash model that delivers 15 watts -per-channel into 4 ohms from 20 to 50,000 Hz at 1% THO. It also features built-in circuit and speaker protection and uses IC's to minimize load distortion at high power ratings. The amp lif ier measures 6"1" X 2'1, X 6';' inc hes. Model KAC-80 1 is priced at $219 ; Model KAC-727 is priced at $95. -Kenwood Electron ics, In c., Dept. P, 1315 E. Watson center Rd., Carson, CA 90745. R-E

sinclair Multimeters Repeatable Quality at Unrepeatable Prices! Take advantage of this super special offer of professional quality DMMs.



Hand-held 3 'h digit LED Multimeter 1% basic DCV Accuracy 16 ranges: DC/ AC Volts . DC Current , Ohms. Resolution 1mV / 0.1nA I lohm Ranges to l000V / loomA / 10M Battery operated (PP3) or AC Adaptor Complete with test leads and carrying pouch

DM235 Bench/ Portable 3 'h digit LED Multimeter 0.5% basic DCV Accuracy 21 ranqes: DC and AC Volts and Current, Ohms Resolution 1mV / llJA / lohm Ranges to l000V / lA / 20M Battery operated (4 'C' cells) or AC Adaptor Complete w ith test leads

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Bench / Portable 3 'h digit LED Multimeter 0.1% basic DCV Accuracy 34 ranges: DC and AC Volts and Current, Ohms Resolution iooov / lnA / O.lohms Ranges to 1200V / lOA / 20M . Battery operated (4 ' C' cells) or AC Adaptor Complete w ith test leads

DM450 Bench /Portable 4 'h digit LED Multimeter 0.05% basic DCV Accuracy 34 ranges: DC and AC Volts and Current , Ohms Resolution lOlJV / 0.1nA / 0.01 ohms Ranges to 1200V / lOA / 20M Battery operated (4 'C' cells) or AC Adaptor Complete with test leads








-------------------------------~~ please send me .. .. .. .... _ _ PDM35 Hand-held DMM @ $39.95 each : $ _ _ DM235 Bench /Portable DMM @ $69.95 each : $ _ _ DM350 Bench /Portable DMM @ $99.95 each: $ _ _ DM450 Bench /Portable DMM @ $129.95 each: $ _ _ AC Adaptor for PDM35 @ $4.95 each : $ _ _ AC Adaptor for DM235 @ $4.95 each : $ _ _ AC Adaptor for DM350 @ $4.95 each : $ _ _ AC Adaptor for DM450 @ $4.95 each : $ Shipping /Handl ing at single rate per order :$ New Jersey residents add appropriate Sales tax: $

I enclose .. .. .. .. .. _ _ DCheck OMoney Order OMaster Charge DVisa _ _ (Allow 2 - 3 weeks clearance time for personal checkSl _ _ Credit Card No. Exp. Date _ _ NAME __ _ _ STREET -CITY STATE ZIP 5.00' SEND TO: NJS Technology Inc . P.O. Box 8247 Haledon TOTAL : $ New Jersey 07538 Tel. (201) 790 3141

















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Haven't you felt f rustra ted beca use you r profits seem to f lyaway before you can put them in your pocket ?


What you get from yo ur NESDA membe rship can help you keep more of , . the money you take in . ~-_... WA NT 9 MORE GOOD REASONS T O JO IN NESDA? ~_ 2. In r y information ,~_......, 3 . Servi ceSh c p magazine . ~~.~ 4 . Electronics Service I I n du st r y Yearbook ~' 5 . Advocate for better warrantv practices 6. Gr ou p-rat e insurance 7 . T ec h nic al information 8 . Ma nageme nt information 9 . Legislative programs with state and nat 'l. gov~s . 10. Low Ban kCard rat es

$:' .

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I More information on computer products is available. Use the Free Information Card inside the back cover. TOUCH SCREEN DIGITIZER , TSD-1 2, elimi nates the need for keyb oards and light pens at computer term inals. To select an item from the " menu" presented on th e screen, all the operator has to do is touch his finger. to it .

te m and pr ogram d iscs can be run at the same ti me, giving fast and efficie nt access to pro grams and dat a and making disc dupli cation sim ple. Kit price is $595 and includ es one drive. A second drive, th e H-1 7-1 is available for $325. A facto ry-ass embl ed version, the WH-B7i nclud es both

Don 't let y o u r buc ks get get l ost in the shuffle At NESDA, the bottom line is pu tting more $$$ in your pocket.


and your local and state associa ti ons Send for more i nf o rmat i o n : NE SDA, 2708 W. Berry St. Fo rt Wo rth , T X 76109



CIRCLE 121 ON FREE INFORMATION CARD Applications include: executive data-base interact ion, computer-aided instruction, voter registration, banking, and othe r situatio ns where an operator must interact with a comp ute r data base. Prices range from $950 for a unit with parallel unfiltered data outpu t to $1,200 for one with filtered RS-232 output and power suppl y. A special one-time evaluation unit with RS-232 interface and power supp ly is availab le for $995. OEM pr icing is availab le upon request.-TSD Display Products, Inc., 35 Orvi lle Drive, Bohemi a, NY 11716. CP/M-COMPATIBLE DESKTOP MICROCOMPUTER series, the Quay 500 and 520 is based on Quay's 94F/ MPS single-board co mputer with 32K of RAM (expandable to 64K). Both syste ms use two 5'/.-inch disc dr ives with DMA . The mode l 500 has a storage capac ity of 400 kilobytes (for-

CIRCLE 123 ON FREE INFORMATION CARD driv es and is priced at $1195. An adaptor kit, the H-BB-6 ($50) is requ ired to install th e WH- 77. All prices are F.O.B. Benton Harb or, MI).-Heath Company (a subsidiary of Zenith Radio Corporation ), Benton Harbor , MI 49022. MUSIC SYNTHESIZER for th e TRS-BO, The M usic Box, is a complete hardware/so ftw are t ool th at enables you to generate music and sound effects using your computer. The Music Box can play up to four not es simul taneou sly and has a range of seven octav es. The waveforms generated can be modi fied so that the music can sound as if played by as many as four diff erent instruments at the same time. In addi -



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matt ed), single-sided, doubl e densit y, and the 520 uses dou ble- sided, double-d ensity dr ives to give over 800 kilobyte s of st orage. A parallel and serial port are stand ard and two additional serial ports can be added. An S-100 bus adaptor is also available. The systems come with the CP/M Version 2.2 operating system . Prices for th e 500 and 52 0 are $2,500 and $3,200, respect ively.- a uay Corporation, P.O. Box 386, Freehold , NJ 07728 . ADD-ON FLOPPY DISC system , the H-77, increases th e sto rage and progr amm ing capab ilit y of the Heath kit H89 com pute r. The H- 77 uses stand ard 5.25-inch, hard secto red, 40- track discette s, each capabl e of storing 100K of data. Typical sector-access tim e is less than 250 millisecond s. Add ing the H- 77 t o the H89 means that , not only is sto rage capac ity increased, but both sys-

CIRCLE 124 ON FREE INFORMATION CARD tlon , a variety of sound effects and noises, such as explosions, gun shots , and " phasors," can be produced. Connecti on is made to the TRS-BO keybo ard or expansion interface by means of a cable. The Music Box includes a volume control, audio amplif ier and jack for connection to an external speaker or amplifier. Software is suppl ied on Level ll cassette or disc. A Level II computer with 32K or more of memory is recommend ed . Price is $249 with softw are and user's manual. Add $3 for shipping and $ 1 more if COD.-Newtech Computer Systems, Inc., 230 Clint on St., R-E Brooklyn, NY 11201.

Put Professional Knowledge and a

COLLEGE DEGREE in your Electronics Career through


STUDY More inform a tion on new lit is available. Use the Free Informa tion Card inside the back cover ELECTRONICS CATALOG, 55 pages, lists a variety of quality parts fro m over 40 manuf actur ers. Covered are regulato rs, capacit ors, resisto rs, transisto rs, IC's , soldering irons, and hundreds of othe r products . Price info rmation and order form includ ed. -Tri-Tek, Inc., 7808 N. 27th Ave., Phoenix, AZ 8502 1. CIRCLE 99 ON FREE INFORMATION CARD MICROCOM PUTER BOOKS , is a 14-page broch ure featu ring a comprehensive four-volume series introd ucing micr oc omputers and books on assembly language and logic design . Descriptio ns and complete tab le of content s are provided . Also listed are BASIC software and prog ram man uals, includ ing three business applicati ons p rograms and 76 short pro gram s with cassett e tape for use wit h the Commodore PET. Osborne/ McGraw-Hili, 630 Bancroft Way, Berke ley, CA 94710. CIRCLE 141 ON FREE INFORMATION CARD COMPUTER ACCESSORIES, Catalog No. 112, cont ains 16 pages of software, co mputer board s, systems, pr inte rs, semi conductor s, and PC aids designed for the co mp ute r enthusiast, novice, and businessperson . Each product is descr ibed in great deta il. Quantity and club discounts available.-Hob by World Electronics, 19511 Business Cente r Dr., Nort hridge, CA 91324. CIRCLE 142 ON FREE INFORMATION CARD PERSONAL COMPUTER CATALOG, No.6, contains 20 pages fu ll of boo ks, software, and merchandise for the computer enthusiast. Offered are back issues of pop ular comput er mag azines, and books on various subject s including microcom puters, gam es, business programs, BASIC language, and much more. Their software includes many different games available In cassette or flo ppy disk form . T-shir ts and posters are also feat ured. Order form enclosed.-Creative Computing, P.O. Box 789-M , Mor rist own , NJ 07960. CIRCLE 143 ON FREE INFORM ATION CARD HI-FI CATALO G, is an illust rated 32-p age booklet describing AM /FM ste reo receivers, integrated ampli fiers , AM/FM stereo tuners , frontload cassette decks, audio analyzers, direct-drive turntables, and loudspeaker systems . In addition to photographs and desc riptions, there is an overall set of tab les in the final pages listing specifica tions so tha t the reade r can compare the claims for one mo del wit h another. - H. H. Scott, Inc., 20 Commerce Way, Woburn, MA 01801. CIRCLE 144 ON FREE INFORMATION CARD TWO-WAY MOBILE RADIO CATALOG, 1980, is an 8-page illustrated brochure covering base station equipme nt, remote -co nt rol equipment, mo bil e car teleph one equipment , mo bile rad io equipm ent, paging equip ment, and portabl e radio equipment, including two-way portable radios .-Mob ile Technical Service Corp., 6019 South Kenton Way, Englewood , CO 8011 1. CIRCLE 145 ON FREE INFORMATION CARD ARCHER SEM IC ONDUCTOR REPLACEMENT GUIDE, 1980 edi tion, is a 224-p age book, featuring cross-re ference/substitution listings for over 100,000 dev ices . It's a comprehensive guid e to Radio Shack' s comp lete line of Archer - brand

semiconductors and includes detailed data and pin conn ection s for IC's , diod es, SCR's, LEO's, and other devices. There is info rm ation on the care of transistors and integrated circuits, case styles and dimension s, transistor testing, di splay and opto electronic devices . A glossary of word symb ols, and abbreviat ions is also included. The 1980 edition of this repl acement gUide is $1.99 and can be ob tai ned from participating Radio Shack stores and deale rs throug hout the U.S.A.-Radio-Shack, 1300 One Tandy Center, Fort Worth , TX 76102. CIRCLE 146 ON FREE INFORMATION CARD MINI-SCOPE SELECTION GUIDE 1979, is a fullcolo r, 4-page leaflet pr esentin g photos and brief specifications of mini-scopes (general-purpose, portable oscilloscop es that weigh 15 lbs. or less, are small enough to fit into a to ol kit or briefcase, and can oper ate from self-c onta ined batt ery power ) and mini-scopes with OMM-counters. The back cov er gives detail ed orderi ng information and a list of sales repr esentati ves in U.S. metropolitan areas.- Vu-data Corporation, 7170 Convoy Court, San Diego, CA 92111. CIRCLE 147 ON FREE INFORMATION CARD

DEGREE by co rrespondence, while co ntinuing your present job. No commuting to class. St udy at yo ur own pace. Lea rn from complete a nd ex plicit lesson mat erials, with additional assista nce fro m our home-stud y instructors. Adva nce as fa st as yo u wish, but ta ke all the tim e yo u need to master each top ic. T he Gr antham electro nics degree progra m begins with basics, leads first to the A.S.E.T . degree, a nd then to the B.S.E.T. degree . Our fr ee bulletin gives complete det ails of the program itself, th e degrees awa rded , th e req uirement s fo r each degree, and how to enroll. (We a re locat ed at 2500 S. LaC ienega BI., Los Angeles, Ca lif.) Write to our mailin g add ress show n below for

Bulletin R- SO

Grantha m College of E ngineering P. O. Box 35499 Los Angeles, California 90035 Worldwi de Career Training thru Hom e Study

TURNTABLE/CASSETTE CATALOGS, Dual turntables and Dual cassette decks . Each catalog contains 12 illust rated pag es. The turnta bles all feature ULM ( LAtr a Low Mass) ton earm s and cartr idg e systems and models range from single play to full y automati c. The cassett e decks feat ure the new OLL (arect Load and Lock) system. Charts on the back covers give a breakdown of the specific features to be found on each mod el, and photos shows how they are laid out.-United Audio, 120 So. Columbus Ave., Mt. Vernon, NY 10533 . CIRCLE 148 ON FREE INFORMATION CARD KESTER SOLDER (NEW EDITION) is an illustrated , two- color, 12-page brochur e covering Keste r's broad line of solders and flu xes. The brochure covers acid and resin- cor ed sold ers, flux-cored silver bearing solders, and radiator solder, as well as Kester's half-pound spools of acid-core, solid wir e and " 44" resin-core solder s. Also desc rib ed are pac kage-goods solde rs and oth er carded merchand ise -metal mend er, TVradio sol der, aluminum -repair solde r, solder paste flux, and related chemi cal products. A special featur e is questions and answers abo ut solderi ng, and a 6- step instruction on soldering proced ure.- Kest er Solder, 4201 Wri ghtwo od Ave., Chicago, IL 60639. CIRCLE 149 ON FREE INFORMATION CARD SAMS COMPUTER BOOKS , 1980 Catalog , conta ins 19 illustrated pages in two co lors describ ing one of the industry's largest select ion of computer and computer-based items. The cata log is laid out in five areas for easy ref er en ce: Basics, Progr ammi ng, Com puter Technology, Reference, and Comp ute r-related boo ks. The selections are directed to a wide range of peopl e and inte rests, fro m the home hobbyist to the techni cally- oriented pro fessional.-Howard W. Sams & Co., Inc. 4300 W. 62nd St ., PO Box 7092, Ind ianapolis, IN 46206. R-E CIRCLE 150 ON FREE INFORMA TION CARD






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JJ ....CO





continued from page 62


low low-frequency signals as continuous level changes and will introduce unacceptable bass distortion. Spectrum division used in the High Com II system solves that problem, too. Since high and low-frequency signals are processed independently, time constants for the high and low-band circuits can be optimized for each particular range of frequencies. The result is extremely accurate reproduction of musical transients, as illustrated by the tone-burst signal (Fig. 6) processed via a High Com II system. The frequency within the tone burst was IO kHz and only a few cycles of that tone were at anything but correct full amplitude after the burst was initiated. Figure 7 is a dual-exposure oscilloscope photo showing the effectiveness of the High Com II system in removing noise components from lowlevel signals. The upper trace was observed during playback of a 400-Hz signal recorded and played back at a level of -40 dB without the use of any noise reduction. Note that the noise amplitude (blurry thickening of the 400Hz sinewave) is not much lower than the signal itself. The lower trace represents the playback of a 400-Hz signal recorded at the same input level,

IlillliiUliilillililiiliililllllllifiiillllilllliiilllllllil1I Fig . 6-EXCELLENT TRANS IENT RESPONSE of Hig h Com II illustrated by 10-kHz tone burst.

Fig. 7-LOW-LEVEL 400 Hz signa l recorded and played back with and without the High Com II.

but this time recorded and played back using the High Com II noise-reduction system. Nakamichi was probably wise to offer the High Com II as an outboard device since it can be connected to any existing cassette deck and, in addition, those listeners who are presently owners of reel-to-reel equipment can also avail themselves of this new noise-reduction R-E system.

Kleps 40


Kteps 10 - 20



HOW TO CONNECT HOME VIDEO continued from page 54

patch panel. Run all of your different inputs and output to a central front panel and use bulkhead fittings and jumpers that have been fitted with BNC type connectors or coax push-on fittings. You want them to be secure but easily rearranged depending on how you are currently routing the signals. If you try to use a switching network in this type of system you can expect problems . (Isolation within the switch becomes a critical factor so if you want to use a switching network, spend the money for good quality switches). You might find that it is necessary to trap out one particular channel to make room in the system for insertion of a pay-TV device or additional VCR. Use a high-Q type trap that will effectively drop out the desired channel without affecting any adjacent channel. If you use the installations that have been described as guidelines, you should be able to set up your own home video system to meet all of your particular needs. R-E


Kleps 30

Clever Kleps Test probes designed by your needs- Push to seize, push to release (all Kleps spring loaded). 10. Boathook clamp 'gr ips wires, lugs, termina ls. Accepts banana plug or bare wire lead. 4314" long. Kleps 20. Same, but 7" long. Kleps 3D. Complete ly flexible. Forked-tongue gripper. Accepts banana plug or bare lead . 6" long. Kleps 40. Complete ly flexible. 3-segment automatic collet firmly grips wire ends, PC-board termina ls, connector pins. Accepts banana plug or plain wire. 6 1/4" long. Kleps 1. Economy Kleps for light line work (not lab quality). ll2" Meshing claws. 4 long. Pruf 10. Versatile test prod . Solder connection . Molded en phenolic. Doubles as scribing tool. "Bunch" pin fits banana () jack. Phone tip . 5112" long.

! ~\ I


~ Write for complete catalog of - test probes, plugs, sockets,



iIJ 6

~ a:




A vailable through your local Pm 10 distributor, or write to: ~ RYE INDUSTRIES INC. U.~ 132 Spencer Place, Mamaroneck, N.Y. 10543 In Canada: Rye Industries (Canada) Ltd. •


earphones, headsets, miniature components.

o Books.

Lists 100 books, games, records, prints, etc. for educational and personal users of small computers.

! !.ep_s ,_ 4 0_.~

Kleps 1

Software. Lists 400 programs on 70 tapes and disks. For education, recreation, and personal use.




Peripherals. (ALF music synthesizer and VersaWriter for the Apple II). Send 3 15 ¢ stamps for either catalog or 5 for both . Or send $2.00 for a sample issue of Creative Computing and both catalogs.

GPootivo GomputinfJ DEPT. REHG P.O. Box 789-M Morristown, NJ 07960

MINIPROCESSORS: FROM CALCULATORS TO COMPUTERS, by David L. Heiserman. TAB Books, Blue Ridge Summ it, PA 17214. 196 pp. 5 X 8'/. in. Sollcover $5.95; hardcover $9.95. This book teaches the computer hobbyist how to t urn a ca lcu lator into a functional hy bri d calculator/computer system (or supercalculator) by add ing on memory-control circuit boards, I/O boards, branching and looping systems, etc. You first learn how to build a basic arithmetic calcu lator, and t hen proceed step-by-step to a fu lly pro grammab le system with randomly add ressab le 256-step memory. Construction tec hniques are given plus fu ll circuit description, component specs and schematics.

Now that it's legal and possible to own your own telephone system, this book provides an answer to the most com mon questions, such as how to go abo ut getti ng your ow n pho ne, the types availab le, and what is or isn't permissi ble to do according to FCC regul at ions. Chapter 2 describes how a te lephone works and how it is inst alled. Chap ter 4 details the FCC req uirements for both owner and te lephone company. Other chapters descri be types of pho nes (picturephone, speakerphone, cordless, et c.) security devices and mobile units . HEAR ALL THE ACT ION, by Van Wate rford. Howard W. Sams & Co ., Inc., 4300 W. 62 St ., Ind ianap ol is, IN 46268. 128 pp. 5'1. X 8'/. in . Sollcover $5 .25. The book guides th e hob byist th rough t he wor ld of inte rnat iona l co mmunications via the OX receiver. It sta rts wit h a hist ory of DX'ing and a description of rad io-wave fundamentals such as frequency, VHF/UHF bands, wavelength, etc . Chapter 2 tells you how to shop for a receiver ; Chapter 3 describes accessor ies and aids ; and Chapter 4 dea ls wit h ante nnas. An appendix con tains a glossary of te rms and lists t he abb reviations and codes used in shortwave t ransmissions.

THE MULTITRACK PRIMER, by Di ck Ros m in i. TEAC Corp. of America, n33 Telegraph Rd., Montebello, CA 90640 . 46 pp. 8'1. X 11 in. Sollcover $4.95. This booklet acquaints readers with multitrack recording and covers all the basics from setup and layout to cue systems and mikes . It covers such top ics as design ing a basic studio for a onema n keyboard or guitar, and shows you how to build a tent and baff le. The te xt is accompanied by charts and line drawings. ALL ABOUT TELEPHONES, by Van Waterford. Tab Books, Blue Ridge Summit, PA 17214. 190 pp. 5 X 8'1. in. Sollcover $4 .95.

RADAR DETECTOR HANDY MAN UAL , by Van Waterford. Tab Books, Blue Ridge Summit, PA

17214. 79 pp. 5 X 8'/. in . Softcover $2.25 . This handy guide to radar detectors explains the principles, Insta llation and use of these devices, and tells you how to detect hig hway police radar signa ls. It also desc ribes how the detectors work, and gives details on radar ci rc uitry . The book incl udes handy hints on how to avoid speeding vio lations, plus a chapter on the CB lingo used In reference to police rada r. THE CAMEO DICT IONARY OF CREATIVE AUDIO TERMS. Creative Aud io & Musi c Electronic s Organization, 10 De lmar Ave nue, Fra m ingham, MA 01701 . 100 pp. 5'1. X 8'1. in. Softcover $4 .95. This first comprehensive dictionary of creative audio te rminology that has ever been com pil ed is aimed at the reader who is not tec hnica lly Incli ned . The defi nitions, from "A-B test" to "zenith adjustment" are brief and clear ly prese nted , with diagrams and tab les where needed. The object of the book is to provide fundamental and working knowledge of creative audio terminology to all who are involved in this field and ind ustry; it wil l be of no less value to t he inte rested read er, too, who may just be curious what some of those words and ph rases that audiophiles use are abo ut. The dictionary was compiled by Gary Davis & Assoc iates and the focus is on sound record ing, sound rei nforcement, and signa l processing for the performing artist. R-E


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CLASSIFIED COMMERCIAL RATE (for firms or individuals offering commercial pro ducts or services). $1.50 pe r word prepaid (no charge for zip code) . . . MINIMUM 15 WORDS. 5% discount for 6 issues, 10% for 12 issues within one year, if prep aid. NON-COMMERCIAL RATE (fo r indiv iduals who want to buy or sell a personal item) 85¢ per word pr epaid . . . no minimum . ONLY FIRST WORD AND NAME set in bold caps. Additional bold face (not availab le as all caps) at 10¢ per word . All cop y subj ect to publ isher's approval. ADVERTISEMENT S USING P.O. BOX ADDRESS WILL NOT BE ACCEPTED UNTIL ADVERT ISER SUPPLI ES PUBLI SHER WITH PERMANENT ADDRESS AND PHONE NUMBER. Copy to be in our hands on the 26th of the third month preceding the date of the issue (i.e., August issue closes May 26). When normal clos ing date falls on Satu rday, Sunday, or a holiday, issue closes on preceding work ing day .

Satellite T~ FOR THE HOME

Sick of Netwoft( TV? Our _ _ lela you get


aIon dI.-ct1y !rom _ orbiting . - TV NI.IIIIM':

H80, Showtlmo, auper at. tiona, aporta ond mem.a !rom oround tho world.

WANTED PRE-WWII and early te levision sets wanted . Will pay top dollar for any set feature d in June RadioElectronics issue ARNOLD CHASE, 9 Rushleigh Road, West Hartf ord , CT 06117 SONY TC105 tapecord er. TIM McNEAL, Box 904 , Warsaw, IN 46580 WANTED . Programm ing manual for Inforex 1302 system compu ter, write to, CHRISTOPHER CASEY, Apt. 240474 -A Coffield , Rt. 1, Box 150, Tennessee Colony, TX 75861

EDUCATION & INSTRUCTION UNIVERSITY degrees by mail! Bachelors, Masters, Ph.D's . . . Free revealing details. COUN· SELl NG, Box 317-R E9, Tust in, CA 92680

24·hour C.O.D Hotline (305) 339· 7600 SPACECOASTRESEARCH

PICTURE TUBE MACHINE We bUy and , . 11 NEW an d USED CRT r ebuil d i n g m achin e ry . COMPL E T E TRA ININ G. Buy with CONFIDENCE fro m the ORIGINAL MFGR . For comp lete deta ils send name. address ,

HOME study degree program in electronics engineering . 75 specialized courses also available . For info rmation write : CIEE, P.O. Box 9196, Pittsburgh , PA 15224


Dept. T, P.O. Box442, AltlmonteSprings, FL 32701


to '

LAK ESIDE INDUSTRIE~ 4071 "N. Elston Avenu e

THE Illust rated Dictionary of Electronics 868 pps send $14.98 to : SDG RESEARCH, 3947 Delta, Rosemead , CA 9 1770

ANTENNA azimuth and elevation fo r all Western Hemisphere geostationary satellites. $3.00 and your latitu de and longitude. Free sample SASE. DAVID FREY, Box 2591, Sate llite Beach, FL 32937

ChiulO , III. 60618 Phon e: 312-583-6565

To run your own c las.ified ad, put one word on each of the linea below and lend th is form along with you r check

lor $1.50 per word (minimum 15worda) to:


Our 75-page c.talog and Inlannatlon book tell the whole etoryl lnexpenalve dllhel, high pro-fMcll, computer aiming softwarel Specl, Illtl and ITlOI1I I Send S7.95 today l

io-Electronics, 200 Park Avenue South, N.Y., N.Y. 10003

ORDER FORM PLE ASE INDICATE in which category of classified advertising yo u wish your ad to appear. For special headings, there is a surcharge of $10. ) Plans/Kits ( ) Business Opportunities ( ) Education/Instruction ( ) Wanted ()

SATELLITE lelevision-New package includes: Antenna aim ing data computed for your latitude, longitude, (plotted by Comp usat), revised listi ng of U.S. and international geostationary satellites, transponder video frequ encies, audio subcarriers, formats, antenna/feed line data and more. All for $10.00, COMPUSAT, 643 South Route 83, Elmhu rst, IL 60126


) For Sale


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Amust forall homeowners andllo·rt·)Ilur>elfers. Build aVideo System thewhole fami ~ canenjoy! No commerc~ l ~ FREE 1tlO'Iies. sports and Vegas Shows · worldwide, crystal clear reception connects to any TV set. 100 pages(8 x 11) load ed with photos, plans, ijts · TElLS






















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GRAPHIC EQUALIZER TWELVE bands/channel $100.00 kit still available; see May 1978 R/E cover story or writ e: SYMMETRIC SOUND SYSTEMS, 912 Knobcone Pl, Dept. R, Loveland, CO 80537




DEALERS : send letterhead for free wholesale pricelist of CB rad io and scanner equipment. FOUR WHEELER COMMUNICATIONS, 10-R New Scotland Ave., Alban y, N.Y. 12208 (518) 465-471 1


~ ... speclalists In CCTV


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a: 106


Video monifWs - colli' ~ BIW • TV cameras , kits, parts ~ plans * V deo-to-RF modulatll's * Free cata og. Phone II' write. (402) 981-3111 I3-RE Broadway Dakota City, HE. 68131



Zeoo1 $195.00 16BFlCPU wIth segmenled address space

10 8 Megabytes. ZSOO2 $150.00 16 Bit CPU WIth non segmented address space 10 SCKbytes,

All Products Stocked in Depth Largest Zilog Inventory zs e-csu 2.5 ZaoA·CPU 4 0 180-PIO 25 ZaoA·PIO 4 0 Zao·CTC 25 ZIOA ·CTC 40 180-0MA 2.5 180A·OMA 4 0


ZIO- SK>/O ZaoA·SIO IO Z80-Sl0 /1 ZIOA ·SlO/ l 280-S10/ 2 ZIO A-SlO/2

2.5 MHz 40 MHz 25 MHz 40 MHz 2.5 MHz 4.0 104Hz

1980 IC MASTER 30.50 36.70 36.00 44.10 36.00 44.10

74LS2ON .29 74LS21N .34 74LS26N 1.45 74LS27N .54 74LS3ON .24 74LS32N .51 74lS38N .38 74LS40N .24 74LS42N .58 74LS47N .88 74LS48N .88 74LS51N .34 74LS54N .21

.29 .22 .59 .27 .58

.69 .38 .59 .28 .48 .19 .34 .87

PIIrtNo. 8080.0 8085

Price $5.85 11.85

P. rt No. 6800 6802

8212 8214 8216 8224 8226 8228 8238 8251 8253 8255 8257 8259

2.75 3.85 2.85 3.45 2.95 4.98 4.88 8.95 10.85 6.95 10.95 12.95

6810 6820 6821

74LS95N 74LS96N 74LS107N 74LS109N 74LS112N 74LS122N 74LSl 23N 74LS124N 74LS12SN 74LS126N 74LS132N 74LS133N 74LS136N

74LS55N .27 74l S73N .54 74LS74N .89 74LS7SN .88 74LS76N 1.24 74LS76N ,45 74LS83N .114 74LS85N 1.34 74LS96N 1.28 74LS80N .54 74LS91N .84 74l Sll2N 1.18 74LS93N .38

.88 .... .58 .88 .48 1.18 1.49 2.95 1.25 .48 2.85 .89

" VERY SPECIAL $39.95"

P.rt No.


$8.50 11.95

6502 6504 6505

SU5 U5 9.85


8.95 9.85 13.85 13.95

3.75 4,85 3.75 3.85 3.75

6850 6582


6532 6551

.68 .114 .114 1.38 2.48 2.45 .84 .49 1.21 1.75 1.18 1.45 1.75

74LS161N 2.45 74lS162N 1.95 74LSl 63N 2.45 74LSl 64N .88 74LSI 65N 2.114 74LSl66N 5.17 74LS1lI9N 12.85 74LS17ON 1.85 74LS173N .88 74LS174N .57 74LS17SN .57 74LS181N 2.85 74lS1 9ON 1.45

74LS191N 74LS192N 74LSl93N 74LSl94N 74LS19SN 74LSl96N 74LS197N 74LS221N 74LS24ON 74LS241N 74LS242N 74LS243N 74LS244N

2.50 .85 1.&5 2.45 .114 4.18 1.09 1.24 1.48 1.19 1.75 .97 1.75

74LS245N 74LS247N 74LS24SN 74LS249N 74LS251N 74LS2S3N 74LS257N 74LS258N 74LS259N 74LS260N 74LS266N 74LS273N 74LS275N

Cl060 TICl1 6B TICl268 TJC216B TIC226D TIC2360 T1C246D

.34 .87 1.09 .119 .95 1.45 1.45

5.85 4.85

TMS4060-30 4K (4K x t ) 3 00NS 22 PI N T M S4 060-20 4K (4K x l) 200NS 22 PI N


1.70 .38 1.39 1.38 4,81 4.95 3.88 4,85 4.85 2.45

.34 .88 .29 .89 .85 1.28 1.48 .58 1.48


LM316N·8 LM318CH

1.45 1.75

lM324N lM339N lM346N·14 lM358N·8 LM55SN·8 LM556N·14 LM723CH LM723CN-14 LM725CN-8 LMl33CN-14 LM739CN·14 LM741CH

M O S Static RAM' s

Poi. ,.

:;; ti~~jW4

input TL072CP 1.19 Dual k>w noise TL084CN 1.95 Quad J-FET input L07~ CN 2.35 Ouad low noise


.48 1.75 1.58 1.28 .85


EPROM 'S C2708

C0402 1BE C04022 BE CD4023BE C0 4024BE CD4025BE CD4026BE C0402 7BE CD4028BE CD4029 BE CD4030BE C04033B E C04034BE C04035 BE C04040B E C04041 BE C04042 BE CD4Q43BE CD4044BE

.74 1.18 .37 .52 .28 1.78 .49 .57 .114 .45 1.78 2.78 1.14 .89 1.58 .87 .89 .78

C04046 BE .89 C04047BE .84 CD4049BE .54 C04OSOBE .44 CD4051BE .82 CD4052BE 1.19 CD4053BE 1.18 CD4060BE 1.89 C04066 BE .89 CD4068BE .28 CD4069BE .27 CD4070BE .38 C04072 BE .23 CD4073BE .39 C040 75BE .34 C040 76BE .84 C040 78BE .34 CD4081BE .27

.38 .s9 .38 .49 .88 .89 .89 .55


.48 .89 .89

TMS2532 321< (4096 x 8) 450 ns TMS2716 16K (2K x 8) 450 ns (3 power supplie s) T .!. Version C2716/TMS2516 16K (2 K x 8) 450 n s (Single 5 V supply - Similar to TMS2564 64 K (81<x 8) 450 ns

$ 6 .95

$ 69.95

14.95 3.95

Specl.' 3.95

$ 18.95 $ 14.95

Itel version) $395.00

5101 1K (256 x 4) 4SONS22 PIN LowPower 4K CMOS RAM P8504 4K (4K x 1) 5SONS18 PIN 110MW PB514 4K (l K x 4) 4SONS 18 PIN 110MW SHIFT REGISTERS 3341APC FIFO 1 MHZ 3342PC 6« Bit Shtft Register 3347PC 80 Brt Shift Register ECl RAM 10410ADC/H II21 08 256 x 1 Brt Fuly Decoded lSNS 16 PIN





CD4082BE CD4085BE CD4086BE CD4093BE CD4099BE CD4104BE CD4508BE C045 10BE CD4511BE CD4512BE C045 14BE CD45158E CD4516BE C045 18BE CD4519BE C04520 BE CD4522BE CD4526BE

·~ Active ~Eleclranic Sales .cOrp.

8.85 19.95

40 Khz Single 5V SUf.{ C MOS R A M


11< x 8450 ns


CMOS CD4000BE .28 C04001B E .39 CD4002BE .23 C04Q08BE 1.19 C0 4007BE .38 C04008B E .84 C04OO9BE .54 CD4010BE .59 C04011 BE .34 C040 12BE .29 CD4013BE .48 C040 14BE .88 .75 C04015BE C04016B E .44 CD4017BE .n C040 18BE .59 C0 4019BE 1.25 CD4Q20BE .89


C0 M8017


LM741CN·8 LM747CN·14 LM748CN·8 LM1456N·8 LM1488N-14 LM1489N-14 LM3046N-14 lM3302N-14 LM3403N·14 LM3900N LM4136N-14 ULN2OQ3AN

1.75 3.95

o to 40K BAUD 40 PIN

3 .95

.58 .58 .89 .78 .38 .48

74LS379N 2.50 74LS380N 4.70 74LS393N 2.75 74LS395N 2.45 74LS447N .37 74LS49ON 2.45 74LS630N 110.00 74LS631N 110.00 74LS669N 4,85 74LS67ON 4.87

2102-25 IK (IK x t} 250NS 16 PIN P2111-35 II( (256 x 4) 3SONS18 PIN P2112-35 l K (256 x 4) 350NS 18 PIN 2114L LowPower 4K (1024 x 4) 300NS 2147 4K (4K x 1) 55N5 2147 4K (4K x 1) 70NS

~------------------------------------UNEAR I.Co's LM301AN·8 L.M304CH lM307N·8 lM306N·8 lM308CH lM309K lM31 0HC lM311N·8 LM317T

74LS348N 2.85 74LS352N 1.35 74LS3S3N 2.47 74LS3ll2N 11.95 74LS365N 4.88 74LS366N 1.45 74LS367N 1.88 74LS368N 1.84 74LS373N 1.83 74LS374N 1.93 74LS375N 4.40 74LS377N 1.52 74LS378N 1.85

Pa rt No.


:::tgr,g~ 2:~~ ~~ power :::tg:~~

1.45 4.25




4 16 -5 (300NS) Ceramic

.IS 4.76 1.00 1.45 1.48 8.93

74LS279N 74LS28ON 74LS283N 74LS29ON 74LS293N 74LS295N 74LS298N 74LS299N 74LS32ON 74LS321N 74LS322N 74LS323N 74lS324N


SCR 5 amp 400V TO-22O SCR 8 amp 200V TO-22O SCR 12 amp 200V TO·22O Triac 6 amp 200V To-220 Triac 8 amp 400V TO·22O Triac 12 amp 400V To- 220 Triac 16 amp 400V To- 220


4 16 -3 (200ns) Ceramic

4.84 .68 1.&9 .89 2.ll2 .84 .85

R's and TRIA '5




Complete integrated circuit data seJea:)r. Master guide to the latest I.e .', lnduding microprocessors and consumer circuits. 45.000 device types ist ed . 5.000 new device types added. Complete new section on MPU board,' & Systems .

74LS137N 74LSl36N 74LSl39N 74LS145N 74LS147N 74LSl4SN 74LS151N 74LS1S3N 74LS15SN 74LSl 56N 74LS157N 74LSl58N 74LS16ON


I-------------------~ I 16K MOS DYNAMIC RAM'S (16 PIN)


over 2700 PAG ES






All circuits In stock for Immediate guaranteed delivery.


74LSOON 74LS01N 74LS02N 74LS03N 74LS04N 74LSOSN 74LS06N 74LS09N 74LS10N 74LSllN 74LS12N 74LSl 3N 4LS14N

10.40 12.05 6.65 1.00 6.65 8.00 22.35 28.00


.23 .82 .78 .114 1.88 1.89 1.88 .84 .74 .88 2.35 2.10 1.28 .89 .59

CD4527BE CD4528BE CD4531BE C0 4532BE CD4S39BE CD4543BE CD45S3BE C04555BE CD4556BE CD4581BE C04582BE C04584BE C04585B E CD4702BE

1.47 .114 .89 1.15 .84 1.49 2.88 .74 .88 1.119


... .... .84 .N




.39 .39 .42 .43 TIP41 .59 T1P42 .64 TIP115 .59 TIP120 .64 T1Pl22 .74 TIP125 .74 TIP127 .85 TIP2955 .83 TIP3055 .70 FT3055 .59


8.95 12.95 15.95


5.50 4045 3.85


OPTO SALE LE0209 LED211 LED212 LED220 LED222 LED224

FN0357 FN0 500 FND507 OL704 OL707 DL747 OL1416 4 digit. 16

IL074 IL0 74 tLCT6 TI1111 4N26 4N33

l .E.D. lAMPS T-1 2mm Red ' T -1 3

.09 .19 .14

mm Green

T·1 3 mm Yellow T-1~ 5

mm Red


mm Green

.11 .24 .18

T-H45 mm Yellow DISPLAYS Common Cathode Common Cathode Common Anode COmmon Cathode Common Anode .830" Common Anode

.375.500" .500" .300" .300"

.89 .89 .89 1.29 1.28 2.28 29.95

segment alphanumeric display 16- ht.

ISOLATORS Dual Opto Isolator Quad Opla lsolalOf' Dual Opto Isolator

Opla Coopler Opto Isolator Opto Isolator

1500V 1500V 1500V 1500V 2500V 1500V

1.28 3.95 1.28 .54 .54 .85

P.O. BOX 1035 FRAMINGHAM. MASSACHUSEDS 01701 O ve I h (' c:ountl"r !>.11(' ~ 12 Me l c e , Rd Na il''' . M ,) !o ~ 01160 Bf' h lOd l .lyn" . on Alf" l} T«,!(' p h o n e Qule , '; & ~'l(lUll ll'" t6i 71 8 1Q,OOll


Fo re i g n <: U 51 0me,s' plea~e re rmt p ay mt."n t o n ,J " mtem a t.en .at b an k cr a tt o r In tern al lo na l PO!>I., ' m on e y cr ce r In Ame u c ..' " d olla rs


1' 4 C At~ A O A

5651 f ERRIE' , S f MONTR EAl. UUE Bf C H4 P 2 K 5 frl tlj l 4jl) 1 7·).11

~:lj~T~~X~~~T;~A6 O TTAWA

"Ie 3P " fr l

om ARlO

.J800 DUFF ERIN S T OOWN SVIEW ONTAR IO M JH 5S9 1 c 1 ( 4 161 b6 1 1 1 1 ~

16131 820 ·9 ~;- 1


5809 M.1ClE O D TRAi l S ' UN IT 109 CAL G ARY ALB ER TA t2 tt OJ9 lei (40JI25q ·6 4)7

3070 KIf;IGSW AY VANCO UVER. O.C VSR 5J7 Tel (604) 4 38 -3 32 1



~ m

:i:: !Xl m Jl ...... <0 00



FOR SALE SCANNER/monitor accessor ies- kits and factory assembled. Free catalog. CAPRI ELECTRONICS, Rout e 1R, Canon , GA 30520 FREE cat alog, IC's, LED's, semi's, parts . CORONET ELECTRONIC S, 649A Notre Dame W., Montreal, Que., Canad a H3C lH8. U.S. inquiries. RECONDITIONED test equipment. $1.00 for catalog. JA MES WALTER TEST EQUIPMENT, 2697 Nickel, San Pablo, CA 94806 SAVE up to 50% on name brand test equipment. Free catalog and price list. SALEN ELECTRONICS, Box 82-M , Skokie, IL 60077 The World's Hardest 1.0. Test as featured In Omn/, April 1979 Qualify ing examination for Four Sigma Society Taken by more than 20,000 people. $5, Including score report. A/so avallab/e:

The Two Cultures Test ($5) (Tests knowledge of science and humanities.) The Vocabulary Gradient Test($3) Send SASE for complete list . POLYMATH, DEPT.R P.O. Box 795, Berkeley, CA 94701 MICROWAVE TV downconverter, preamps , parabolic dish antennas, remote tun ing. Covers 2000 MHz band. Write for informati on. LAB-TRONICS, Box 171, Rogers, MN 55374 GIANT com munications guide. Info thru 1980. Worldwide LW- AM- FM- SW- RTTY- CW- Faxsatellite -VOL MET- marine- NOAA- QSL'S- etc . $20.00 ppd . GCG, 11625 W. McKinley, Fresno, CA 93711

1. 5 Volt, 3 amp, Regulated Power Supply. Gre at for TT L Proj ect s $19.50 2. EMM 4200A, 4K Static RAMs, Ceramic A lo cal m em ory b o ard s m anufacturer cl o sed . We b ought th e ne w m emory b oa rd s and took the se 4200A stat ic RAMs o ut. They are tes t ed and 9D-d ay gua ranteed 100 % good. Prime tested 4200A 4K RAMs $5.50 ea . 3. Super Saver. M icro PD4 11. Cera mic 4K x 8 for $10.00 . 1 d yna m ic RAMs WE BUY SURPLUS ELECTRONIC INDUSTRIAL INVENTORIES

RECORDS-tapesl Discounts to 73%; all labels; no purchase obligations; newsletter; discount div idend certificates; 100% guarantees. Free details . DISCOUNT MUSIC CLUB, 650 Main Street, Dept. 3-0980, New Rochelle, NY 10801 VOLCANIC ash from Mount Saint Helens; glass container filled with ash, plus description. Send $4.00 to : ASH, 5268 35th N.E., Seattl e, WA 98105 KEYBOARDS-High quality 61 note single or dual contact for the organ or synthesizer you are building. Send for information. DEVTRONIX, Dept. 70, 6101 Warehouse Way, Sacramen to , CA 95826


COMPLETE gear for CB repair shop, including Sencore CB 42 analyzer. TED MARSHALL, 1605 South Main, Warrenton, OR 97146

5151 BUFORD HIGHWAY .... DlI ATLANTA. GA 30340 . 404..58-4&90

RAW speakers and finished systems for Hi-Fi and Sound Reinforcement. Also cabinet plans , hardware , grille cloth, crossovers, microphones, accessories, much more. Info rmation-packed catalog, $1.00. UNIVERSAL DISCOUNT SOUND, Dept. RE, 2243 Ringling Blvd , Sarasota, FL 33577 GOVERNMENT surplus receive rs, tra nsmitte rs, snooperscopes, parts , fantastic 72 page cata log 25¢. MESHNA, Nahant, Mass. 01908

Burglar· Fire 11\.£ Protect Your Life, Home, Business, Auto, ete. , .

• Our catalog shows how. Install your own alarmsystemsand devices and save SSSS. We


.-::=-::...-.. offer FREE write-in engineering service. 'FREE CATALOG ....: :::..:.:-:-...t.;•••,,'

BurdexSecurityCo. Box 8Z80Z·HE lincoln, He. 68501

CABLE TV converters $39.95. Incred ible 96-page cata log free. ETCO, Box 762, Plattsburgh, NY 12901

FREE shipping . Liberal discounts. No risk guarantee. Why pay more for your electronic and computer books. Send stamp for list. MICROPOWER BOOKS, 17095 Bridgeport Road, Dallas, OR 97338


NEW-scope, VOM and more . To best offer. Write ERVIN WARREN, Drawer R,· Huntingdon , PA, 16652. Phone 215-444-5879

Lasers Super Powered, Burning Cutt ing. Rine. Pistol. Poc ket. See in Dark-Sh otgu n Directiona l Mike Unscramblers-Giant Tesla - Stunwand-TV Disrup ter- Energy Produ cing. Surveillance, Detecti on, Electr ifying, Ultra soni c. CB, Aut o and Mech . Devices. Hundre ds More - All New Plus INFO UNLTD PARTS SERVICE. Catal og $1. Information Unlimited. Dept. RS Box 716 Amherst, N.H. 03031.

TELEVISION downcon verters and decoders $99.95 up. Details for stamp. GW ELECTRONICS, POB 688, Greenwood, IN 46142 OSCILLOSCOPE, DC to 22 MHz, dual trace , Navy equivalent to HP170, $199. HAMMOND, 1013 Lafayett e Avenue, Colon ial Heights . VA 23834

SCRAMBLED television, encoding/decoding. New PUblication . Theory/circuits. $9.95. WORKSHOP, Box 393 REA, Bethpage , NY 11714 TEST equipment, new and used. Catalog $1'.0 0. PTI, Box 8756, White Bear Lake, MN 55110

C:SC 6"x9" 3-WaySpeaker • 20 oz. ceramic mag ne~ Model BP200D-69TR ..;-, i $14 9 5



WAHG !§QKill


00 Soldering Iron

Attache Style Tool Case

$29 9 5 Mod.1 7800

Mod.1 TC10il'ST

~~ 95$29995 • Sine-. square-, triangle- and

separaleTIl square wave output•


Service Master Tool Kit Mod.199-SM

$;;~5 $4995

Proto ==:i Proto Board with Preassembled Built-in Power MOd'l~ Boards

~~~~~)e~s~ ~. ~~!;;:~~=:::::;-~~:"",:"-.:-~~~~~L~~ ..2!:~~=:'~

PB-1D4 ~$ 4995 FUlly assembled breadboard • Short-proof contains four QT-59S sockets. Reg . $1 54.95 seven QT-59Bbus stripsand four $1 2 9 9 5 S-way binding posts


o Z o

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is «a:


RC Circuit Box ' .,

. 36 resistors (15ll to 10Mil) • 18 capacitors (l00pfto 0.22 "f) Reg $49.95 $4 2 . includes test leads

rn -~~!

! s.._ "~ "S

'~ . -, "

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"=:...:::.:....::.::-.:. VIZ

Model WC412A

Chess Challenger 7• Reg.$110.00 Mod. 1 $7 9 9 5 BBC


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Magnifier Lamp Preos,on groundand pohsn",

:~n;~''t.l~:S $49 5 0

Dual Trace

~:l:: oelaY :1

$8 9 9 9 5 • ModellBQ·s 20

Weller·Controlled Output Soldering Station ~~~"


_ .~ :

Type 4001 4011 4013 4017 4027 451 1 4049 4050 4066

Schottky ICs Type 74LSOO 74LS02 74LS04 74LS08 74LS32 74LS73 74LS74 74LS75 74LS90 74LS123 74LS151 74LS157 74LS161 74LS164 74LS175 74LS193 74LS367

Cat. No. 276-240 1 276-24 11 276-2413 276-24 17 276-2427 276-2447 276-2 449 276-2450 276-2466


Each .99 .89 1.19 1.99 1.19 1.99 .99 .99 1.59


Cat. No . 276-1900 276-190 2 276-19 04 276- 1908 276-1915 276-19 18 276-1919 276 -1920 276-192 3 276-1926 276-1929 276-1930 276 -19 31 276-193 2 27 6-193 4 276-1936 276-1835

Each .79 .79 .79 .79 .89 .99 .79 .99 1.19 1.49 1.09 1.19 1.59 1.59 1.39 1.69 1.59


Cat. No .


7400 7402 7404 7408 7447 7448 7473 7474 7475 7476 7490 7492 74154 74 192 74193

276- 180 1 276-18 11 276-1802 276 -1822 276 -1805 276-1816 276- 1803 276-18 18 276-1806 276-1813 276- 1808 276 - 1819 276-1834 276- 1831 276 -1820

.69 .79 .79 .79 1.19 1.29 .79 .99 1.09

Rugged ther moplast ic. Prevent shorts . Ideal for audio equipment, power supplies. Terminals extend '¥,e:


Cat. No.



274-651 274-652 274-653

1.19 1.49 1.79





16K Dynamic RAM Ne w !

IC Tool Set


Mini Lamps New! Only

Bullt·ln Pin Straightener

Speaker Terminals


16,384 x 1 bits in a 16-pin DIP. Access time : 250 nanoseconds. Refresh : 1 milli seco nd. Requi res + 5, + 12, and - 5VDC . TTL co mpa tible. 276·2505 13.95

Opto Devices Low As


Just right for hi-fi, instrume nt or PA speake rs. Push-terminals accept up to 16-ga. wi re. Also has 2conductor V4' phone jack with sealing plug. 274-62 4 1.99



Em itter /Det ector Pair. LED infrared source . Sensitive phototrans istor detector. 276-142 1.99 lID Phototran s lstor. Sensitive, fast 89¢ respo nse silicon. 276-130

Cases and Cabi net Save~: 3 3%

99¢ Pkg. ot 6

Long life red incandescents for mode ls, charts , dial lights, more. 6V, 60 mA. 272· 1144 .. . . 6/99¢

Yellow 0.3" LED Readout New! 99



Pkg. of 2 Right hand decima l, 3.0V/ segment (ci 20 mA. Common cathode . 276-067 Pai r/1.99

TV RF Modulator Boa rd Save



1.09 1.19 1.49 1.59 1.49

All 100% Prime from Major Manufacturers. Specs and Pin Out Diagram Included with Each Device.

Back in Stock ! 0.45V at 1 Amp in full sunlight. 276-123 9.99

Enlarged to show detail

Handy insertio n and extraction tools handle all 14 to 16-pin devices . Both too ls easily gro unded .. 276·15 74 Set 6.95


28-Pln DIP SN76477. Music, explosions , phasers, gunshots and more - almost any sound imaginable ! Line-level output. 6-15VDC. With data . 276- 1765 4,49

Reg. 16.95

1 95

~ Deluxe " Woo d Look" Cab in et. Metal. slide-off cover, rubb er feet. 2'¥..4V..5W' 270-262 (Reg. 5.95) Sale 3.95

00 Readout. Holds four 0.6' or eight 0.3- readouts. Removable brac ket. 1 ' '¥1 6X37Alx4~: 270 -285 (Reg. 3.95) Sale 2.95 [fJ Cloc k. For MA -1003 car clock . Blue lens. Accep ts 3 switc hes (not (Reg. 5.95) Sale 3.95 incl.). Bracket. 3 Y.1x2Vsx2: 270-303

16-Pin DIP Jumper Cable

Etched, drilled & labeled PC board with prewired RF module and back-of-set ant. switch. Ch. 3 or 4 out. Produces color or b&w video, 30 -15,000 Hz hi-fi sound. With instructions. Parts extra. 277-122 Sale 11.95

AC Cooling Fan Quiet, Effic ient

Ideal for cooling hi-fi and ham equipment, power supp lies, computers. 70 CFM . For 120VAC. Just 4.63x4.63x 2.47" over all. 273·2 41 14.95

Two 16-pin DIP plugs connected by an 18" color-indexe d ribbo n cable. Simplifies linking up digital circuits . . 276·1976 3.99 Prices may vary at individual stores and dealers

Circuit Breaker Prote cted Powers CBs, ham rigs, auto-sound equipment and more from 120VAC. 2.5A continuous, 5A surge, 2Y.1x4Y.1x6'¥. : U.L. listed. 22-124 29.95

RadiO Ihaell








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BUILD laser using laser diode 1-1200 watts. Plans $4.00 . LASERTRONICS (1) 12320 Spring, Portland, Oregon 97225



PRINTED circ uit boards from sketc h or artwork. Kit projects. Free det ails. DANOCINTHS INC ., Box 261, Westl and , MI48185 SPEAKERS. Save 50%. Build your own speaker system . " Free catalog" write: MC GEE RADIO, RE 190 1, McG ee St reet, Kansas Cit y, MO 64108

ELECTRONIC car horn whi ch toots your favcrite tune at 15 watt s complete with spea ker $69.95 gua ranteed, easy installation . Free details. Kit with simple inst ructi ons $24 .95, name your tune . JHC ELECTRONICS, P.O. Box 1158, Landolakes, ~L 33539

Up to

15 % Discount

PROJEC TION TV . . . Con vert your TV to project 7 foot picture. Results equa l to $2,500 projector. Total cost less than $20.00. Plans & lens $16 .00. Illustrated Infor m ati on free. MACROCOMGA, Washington Cro ssing, PA 18977

on TRS·80's 26·1051 4KLEVEL I. $.424.00 26·1056 16K LEVEL 11 • • • • • • •$715.00


DIGITAL fuel gauge: 2'/. digit, 10 led scal e. All part s, PCB layout, $24 .00; Digit al auto compass/ Plans $3. 50 each, informati on 50¢. TS RESEARCH, 970 Sou th Anah eim ·Blvd , Suit e 113, Anaheim , CA 92805

LOGIC LAB TTL CMOS linear breadboards, function generator, six supplies, indicators, switches $99 .95. CASCADE LABS, 5637 Bayview Avenue, Richmond, CA 94804



Downto wn Plaza Shopping Center

115 C. Second Ave.. S.W. Ca iro. G eorgia 31728

(912) 377-71 20 Ga . Phone No.


ELECTRONIC NEW plans. Telephone memory dialer, negative Ion generator, burglar alarm , $3.00 each . Sub scr iption te levision decoder, $10.00 . Plans includ e detailed instructions and circuit board patterns. COLLINS ELECTRONICS, Box 6424, San Bernardino, CA 92408. DECODE Morse and RTTY signals off the air with new Morse-a-Word or RTTY reader. Morse keyboard also available. Kits or factory wired. Send for details. MICROCRAFT, Box 513R , Thiensville, WI 53092 (414) 241-8144 .

DIGITAL multimeter kits handh eld , best quality 0.1% accuracy. The lowest price in America $67.50 write: E. G. TRONICS , 8254 Greenlea f Circle, Tampa FL 33615

MEASURE microfarads, megohms, moonlight, minutes, motion, more with your constant-add calculator and our $ 14.62 module. Easy "oneevening" projects . Applications manual $ 1.00 (refundable) and large SASE. KALTEK, Box 7462RE, Rochester, NY 14615

TELEVISION alignment - in minutes-while observ ing revolu tionary pattern on screen. Check RF, IF, vid eo, Instantl yl So simple and inexpensive it 's Incred ible. Complete plans-$6.00 . Free det ails. JOHN KOZULKO, Box 2702R , Clearwater, FL 335 17

SAVE 90%. Build your own minicomputer. Free details. DIGITRONICS CORPORATION, 2723 E W. Butler Dr., Phoen ix, AZ 85021

COMPUTER calcul ated earth station data. Pad center line $5.00. Antenna azmuth and elevation $3.00. Need site latitude, Jongit ude and satellite of Interest. Free sample SASE. KEN 'S CATV SERVICE, P.O. Box 54, Red Ash, VA 24640

SUBSCRIPTION TV decoder circuits. Deta iled plans $4.60, JOE PO Box 61, Cumberland, RI 02864




LM3046 RCA40430 CA3086 LMS67 CD4046 LM3302 2SC1849 MPSA20


IC =3A (SA Peak) VCEO =4S0 VDC FOR TV HORIZONTAL SECTIONS; HIGH VOLTAGE REGULATORS REPLACES: 2N5076. 2N5077. 2N6838. 2N566S. BDY94. BU1 26, 2SC2121. 2NS940. 2SC1046. 2N5466. TIP556 AND MANY OTHERS. (CA3046) Transistor Array 400V SA TRIAC TO-66 RCA Transistor Array

75 75 80

T one Decoder .... . . . . . . . . . .. . . . . . •99

PLL CMOS 99 QuadComparator . . . . . . . . . . . . . . . .. .89 High Freq NPN;T0-92 6/1.00 NPN GEN PUR 811 .00

Sound Effects Kit $18.§O The SE-Ol IS . complet e kIt tha t con la lns all the part s to build. progr amm abl e sound eff ects generator . Designed aro und ;: :::: ;:: :: ::~


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lhe new T... .. Ins truments SN76477 Sound C hip, the

bOIird provides banks 01 MIN I DIP sWll ches and po ts to prog ram the var iOUS com binatio ns 01th e SlF O SCillator. veo . Noi se. On e Shot , . nd Enyelope Control s A Quad Op Amp IC IS used to 'implement . n AdJust.ble Pul se Gener . to r. Level Co mparato r .nd Mulltplex Osci llato r for even more verutillty . T he 3 ' ~ x 5~ PC Board l eatur es a pr otot ype ar•• to allow for user added CIrCUItry. E. sll y p rogr . mmed to eu eu c at e Ex p l o s io n s. Phlsor Guns. Steam Traina . o r .I most an InfinIte num bet' 01 other sounds . Th e u mt has • mul tIple 01 . pphcalions The low pnce ,ncl udes . U p.rts. . ssembl y pt'vwr.mmlng ch . rt s. • nd dei . lled 7&477 c tu p Speclhcalton s It run . on • 9V b.ttery (not inc lu ded) . On bo . rd 1ClOMW .mp ""Ill crw e a sm. lI spe.ker dir ectl y. or the un it c.n be co n nect ed to you r stereo "",th incr edIb le result s l (Speaker not ," clud ed) .

• 76471 CHI P IS INC LUD ED. EXT RA C HIPS $3..1 5 EACft

AY3-8910 PROGRAMMABLE SOUND GENERATOR The AY3-8910 is a 40 pin LSIchip with threeoscillators. th ree am plit ude con trols, prog ramm ab le noise generat o r, th ree mi xers, an envelope generato r. and three D/A

converters that are controlled by 8 BIT WORDS. No external pots or caps required. This chip hooked to an 8 bit microprocessor chipor Buss (8060. Z80,6600 etc.) can be software controlled to produce almostany sound. It will playthreenotechords. make bangs. whistles.sirens. gu nshots. exp losio ns. bleets, whi nes, or gru nts. In addition, it has provisions to contro l its own memory

chips with two 10 ports. The chip requires ' SV @ 7Sma and a standard TTL clock oscillator. A truly incredible

Investment unnecessary. knowledge not required. sales handled by professionals . Ideal hom e busi ness. Writ e today for facts I

Postcard will do. Barta-RE-G, Box 248,

Walnut Creek, CA 94597.

BUSINESS OPPORTUNITIES MECHANICAlLY inclined individuals desiring ownership of Small Electronics Manufacturing Business-without investment. Wr ite :BUSINESSES, 92-R, Brighton 11th , Brooklyn, NY 11235 GOLD . . . from electronics, jewelry, scrap. Guaranteed industry procedures, trade secrets. $5.95 (Texas + 30 ¢). AUROTECH , MS106, 2806 Geraghty, Austin , TX 78757 PROJECTION TV . . . Make $200.00 + per evening assembling projectors . . . Easy . . . Results equal to $2,500 projectors . . . Your total cost less than $15 .00 Plans, lens & dealer's information $14.00 Illustrated info rmation free • • • MACROCOMGAX, Washington Crossing, PA 18977

p<Q) ~~ ~<Q)11~~~! ~ @@«[email protected]@J fdXC 1~0iJl!<Q) ~t:.~\


Bul let's Electronic Mu sic Maker" Kit has a single 28 Pin M icroproc essor Chip with ReM tha t has bee n programm ed to play the fir st 6 to 10 notes of th e25 popular tun es l isted be low . Each tu ne can easily be addresse d Ind ividua lly or pl ayed seq uenc ially at th e push of a button . Th e 3 c hime sequences are activa te d at any tim e by sepa rate switc h c losur es so w hen used as a doo rbell , one door can play songs w hile two ot hers w ill play differe nt chi mes. Th e un it has a 5 wa tt au dio Amp and wll l run on eithe r 12VAC or 12VDC . Op tional 117VAC transform er is a....ailab le. Co nst ruction is very simple . works wit h any 8 or 16 ohm speaker. or ho rn speaker. (Not Inc luded .) Tu nes can be remotely program med using as ingle rotary swltc h. (no t included). if desi red. Comple' e KU $16.95


$14.95 W/Basic SpecSheet (4 pages) 60 page manual with S-100 interlace instructions and severa l prog rammi ng exam ples . $3.00 extra .

1/2W RESISTOR ASSORTMENT A good mix of 5' a nd 10" ..... new , trrst quality .

IJes In both full lead and PC lead dev ices . All


Tr ansfo rmer $1.35 (For operation on 117VAC)

Tunea:Tonadof· Wlilam Te. · H.......jah Chorut; · StIWS~Wd BM Mf • Vank.. DoodN · Arnerica. Am ... lea · OeutKf\1and l ekt ·W~M .rch • B....ho'Ien·.5th.ndtth · Heir. B • L.V Ien EnR OH· StlWWarsTheme • ClltfMfttlne • Au U.... • JingJe I God s." The Ou..n· Colonel Bogey · ...tH • 0 SoIeMlo· SMt. l~· TIMEnd· I kle Oenu be · Brahm. Lull aby · We.tmlnl,tar Chime · Slmpfe Ch ime · Deecendlng Ocifte Ch ime.

(A sst] 200 piecesf2.00




ULTRASONIC RELAY KIT INVISIBLEBEAMWORKS LIKEA PHOTO ELECTRIC EYE. USEUPTO 2S FT. APART. COM PLETEKIT. ALL PARTS & PC BOAR DS. $21.50 THE PERFECT TRANSFORMER 117VAC primary. 12VAC secondary @2ooma .. Great for all you CMOS. or low power TIL projects. PC board mount. 99~ eo. 3/$2.50 Size: 1.5" W x 1.2S" D x 1.2S" H









NOW A SUPER READOUT AT A SUPER BU YI These are fKtOfY fres h prkn e LED reado u t s, not s econ ds or rej ec t s as so ld by others. Co m pare ou r price an d send fo r yours today. bu t hurry, the su pp ly is Ilm ited l • lPECIFY : CO MMON ANODE OR COMMON CATHODE

Bar/ Graph Driver ... ..

. . . . . . . 2.50

SV 1ARegulator .. .. .. .. .. 'loA TO-S Reg. SV (Hse.•)


Temp . Tran sducer Timer IC Voltage Reg. 14 Pin Dip

99 .60 1.10 49 50

1A 12V Reg P.U.T. W/Specs


Opto Isolator W/Specs




CORPORATION Quality Electronic Cnm po ne nts

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100W CLASS A POWER AMP KIT Dynamic Bias Class " A" circuit design makes this unit unique in its class. Crystal clear, 100 watts power output will satisfy the mostpicky fans. A perfect combination with the TA-1020 low T.I.M. stereo pre-amp. Specifications: • Output power: 100WRMS into 8-ohm 125WRMS into 4-ohm • Frequency response : 10Hz - 100 KHz • T.H.D.: less than 0.008% • SIN ratio: better than 80dB • Input sensitivity: IV max. Power supply: ± 40V @ 5 amp TA-1000KIT $51.95 Power transformer $15.00 each



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. . .


- --- -

Graphic equalizer have been used for years in sound studios and concert arenas but were too expensive to be considered for home use. Now we offer you the facility at an affordable price. This unit can extend your control of your Hi-Fi system by minimizing the non·linearities of the combined speaker/room systern. Fantastic features as follows: • 10 double slide controls for two channels • Cutout rumble, surface noise andhiss • Minimizesspeaker/room non-linearities • Frequency response from 30Hz to 16KHz • 10 tonecontrols plus defeat, monitor andtape selector. • Control range ± 12dB in 10 octaves (30Hz, 60Hz , 120Hz, 240Hz. 500Hz: 1KHz, 2KHz. 4KHz, 8KHz, 16KHz.) • Operating voltage 117V 50/60Hz. FACTORY ASSEMBLED UNIT, NOT A KIT SPEC IAL PRICE$117.00 ea





This new stereo level indicator kit consists of 36 4color LED (15 per channel) to indicate the sound level output of your amplifier from - 36dB - + 3dB. Comes with a well-designed silk screen printed plastic panel and has a selector switch to allow floating or gradual output indicating. Power supply is 612V D.C. with THG on board input sensitivity controls. This unit can work with any amplif ier from 1W to 200W! Kit includes 70 pes, driver transistors, 38 pcs. matched 4-color LED, all other electronic compon ents, PC board and front panel.

SPECIAL $19.95 ;'

MARK IV KIT $31 .50



It works in 12V DC as well! Kit includes 1 PC SANYO STK-043 stereo powe r amp. IC LM 1458as pre amp. all other electronic parts, PC Board, all control pots and special heat sink for hybrid. Power transfor mer not i ncluded . It produces ultra hi-fi output up to 60 watts (30 watts per channel) yet gives out less than0.1% total har' $32 50 PER KIT monic distortionbetween . 100Mz and 10KHz.

. J

This series cove rs a wide range of level indication uses. output and input voltage, time related change, temperature. light measu rement and sound level. The problem of uneven brilliance often encountered with LED arrangements as well as design problems caused by using several units of varying size are substantially redu ced . 12 LEDs in one bar: LED ARRAY GL-112R3 Red, Red, Red $5.50 GL-112N3 Green. Yellow, Red 56.50 GL-112M2Green , Green, Red 56.50 GL-11 2G3 Green . Green , Green 56.50




trigge~ ~re,.iiiiiiiiiiiiiiiiiiiii~~

• proximity • voltage triggered' • mechanically triggered This alarm protects you and itself! Entering protected area will set it off, sounding your car horn or siren you add. Any change in voltage will also trigger the alarm into action. If cables within passenger compartment are cut, the unit protects itself by sounding the alarm. 3-WAY PRDTECTION ! All units factory assemb led and tested - Not a kit !


MODEL 888 R FEATURES Circuitry: designed for operation by high efficient, high power silicon transistor I which enabie illumination maintain in a I standard level even the battery supply . drops to a certain low voltage. • 9" 6W cool/daylight miniature fluorescent tube. • 8 x 1.5V UM-l (size D) dry cell battery. • Easy sliding door for changing batteries. reflector with wide angle in$10•50 EA • Stainless creasing iumination of the lantern.








LED DRIVERS 1R 2406G is an I.C. specially designed to drive. 12 LEO. The number of LED is lineally illuminated according to the control voltage input terminal 21. Operating voltage is 9 12V D.C. 55.35 EACH DUEL CHANNEL VU METER P.C. BOARD AVAILAB LEAT54.50 EA.





TECT model WEM -16 is a factoryassemb led FM wireless microphone powered by an AA size battery, Transmits in the range of 88-108MHz with 3 transistor circuits and an omni-directional electric conden ser. Element buill -in plastic tube type case : mike is 6'1," long. With a standard FM radio, can be heard anywhere on a one-acre lot; sound quality was judged very good. .-C~=516.50 • ,_.


FLASHER LED Unique design combines a jumbo red LED with an IC flasher chip in one package. Operates directly from 5V-7V DC. No dropping resistor neded. Pulse rate 3Hz @ 5V 20mA.

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2 LM 380 with Volume Control 18V DC ONLY $6.00 EACH

hllm . I Power Suply 6


i 1

A. 0·50UA 8.50 ea. B. 0·30VDC 8.50 ea. C. 0·50VDC 8.50 ea. DISCO LIGHT K IT D. 0-3ADC 9.00 ea. Latest design electronic color light organ. with both E. 0-100VDC 9.00 ea. sound and line input. the three color lights (not in' - " -'~ All meters white face with black cluded) will change colors with the rhythm of the Tvoe MU-52E scales. Plastic cover. music: controlled by 3 ranges, low. middle and high. . .--:---:--....:::=.::.:...;..:::::==~==-:----11 Ideal for party. bar. or home entertainment. Max. con0.5 " LED trolled output 1000 watts per color (3 colors). A L A R M CLOCK MODULE Kit includes aluminum cabinet. all electronic parts, ASSEM8LEO I NOT A KIT! P.C. boar and fransfo er. Features: • 4 digits 0.5" LED Displays > 12 hours real time lormat • 24 hours alarm audio output (Color Organ) • 59 min. countdown timer « 10 min. snooze control. $45.50 per kit ONLY57.00 EACH SPECIAL TRANSFORMER FOR CLOCK , r , ... TY-23 (FREEl "






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WANT TO BUILD YOUR OWN BLACK MAGIC BOX ON TOP OF THE TV FOR FIRST RUN MOVIES? We have all the parts inciuding hard to find UHF variactor tuners and P.C. board. Call us for more lnlormatlon.


With Case Only $6.50 Per Kil

12VDC PDWERED Lights up 8 ~ 15 Walt Fluorescent Light Tubes. Ideal for camper, outdoor, auto or boat. Kit includes high voltage coil, power transistor. heat sink, all other electronic parts and PC Board. light tube not included!

BATTERIES PK/$10.00 ~ I C K E L CADM IUM 2 PKS/$19.00 ' . BATIERY IllUSTRATED ~J PACK LESS COVER -:.:J '0' SIZE Outpu t: 3.6 Volt s @ 3.0 Amp/ HDur. Consists of th ree each. ' . 2 Volt " 0" size Nickel Cadmium Cell s stacked and p last ic fil m encapsulated. Tabs are prov ided at each end for elec-

~r~~~r'edco~na~~~O~:Ch~~~e j ~~:~i~~a~oce~l. C~~}: ~~~r:~ ~~z~ ! ..-:-~-::-:=~----==~~~~~-. 1V4" dia. x 7" lon9 New. Shpg Wt each pack, 1 lb.



This new designed circuit uses high FEQ. FET transistors with 2 stages

p re amp. Transmits FM Range (88-

away andr 120 MHz up tosensitive 2 blocks con with the) ultra dense microphone that comes with the kit. -<:> . ' allows you to pick up any sound within 15 ft. away! Kit includes all FMC-l0 5 electronic parts. OSC coils. and P.C. $11.50 PER KIT Board . Power supply 9V D.C. "


- . ..I

New design body wit~ see thru speaker grill. SPECIAL PRICE S16.50 EACH AU-999




SameastheE-Z clips $2 75 ~ Cut off when circuit is shorted With 20" Long Leads . or ove r load to protect your In Black and Red Colors per pair ampli fie r as weII as your 1t---::-7::.--=:=-:-::=:--:::-:-====:.:::7----1r::...::~~:7.::::_::;::~~=::,...,=_=:_=___:_...:,_speakers. A must for OCL SOUND GENERATOR I.C. circuits. ~AC Creates almost any type of sound - gun shot, exKIT FORM plosion, train. car crash, star war, birds. organ ext. S8.75 EA. 12VAC $2.75 EA. A built-in audio amplifier provides hiQh level output. 16V CT AC $2.10 EA. Operates from one 9Vbattery. 28 pin _ "FISHER" 30 WATT $1.90 EA. 6VDC dip: we supply the datas. $2,90 EACH ' % • 12VDC $1,90 EA. STEREO AMP


Super Buy Only $18.50

MAIN AMP (15W X 2) Kit includes 2 pes. Fisher PA 301 Hybrid IC all electron ic parts with PC Board. Power suppl y ± 16V DC (not included). Power band with (KF1% ± 3dB). Voltagegain 33dB. 20Hz - 20KHz.


ELECTRONIC S.WITC;J .. ,.K . IT CONDENSER TYPE TouchOn Touch Off uses 7473 I.C. and 12V relay $5.50 each







Kit includes theUltra Sonic Transducers, 2 PC Boards ' All parts are pre-assembled on a ~ . for transmitter and receiver. All electronic parts and mini PC Board. Supply Voltage 6 ~ instructions. Easy to build and a lot of uses such as All P.C. boards are made from high quality phenolic. 9V D.C. SPECIAL PRICE $1.95 ea. remote control for TV. garage door, alarm system or counter. Unit operates by 9-12 DC . $15,50 predrill ed in different pattern s for different purpose. I~~~~~~~~~~~-----.:~~_It_-_;_A;;_;;_;:;;;_~~_;:_;==;.;~-_I All boards 1/16" single sided copper. Hol e spacing is LOW TIM DC STEREO COMPLETE TIME MODULE standard 0.1 ", Fits all kinds of I.C. transistors, capaPRE-AMP KIT TA-l0 20 0.3" digits LCD Clock Module with month citors and resistors. Ideal for school projects, engineerIncorporates brand-new D.C. design that gives a and date, hour. minute and seconds. As ing designs andprototyping. frequency response from OHz - 100KH z ± 0.5dB! 6 Y9 well as stop watch function!! Battery Added features like tone defeat and loudness control and back up light is with the module. let you tailor your own frequency supplies to eli. . Size of the module is 1" dia. Ideal foi minate power fluctuation! use in auto panel. computer. instrument Specifications: • T.H.D. less than .005% • T.I.M. and many others! $8.95 EACH lessthan .005% • Frequencyresponse: DC to 100KHz ± 0.5dB • RIAA deviation: = 0.2dB • SI N ratio: betSOUND ACTIVATED SWITCH ter than 70dB • Sensitivity: Phono 2MV 47K/Aux. All parts completed on a PC Board 100MV l OOK' Output level: 1.3V · Max. output: 15V SCR will turn on relay, buzzer or • Tone control: bass ± 10dB @ 50Hz/treble = 10dB trigger other circuit for 2 - 10 sec. @ 15Hz ' Power suppl y: ± 24 D.C. @ 0.5A (adjustable). Ideal for use as door Kit comes with regulated power supply, all you need alarm, sound controlled toys and a is a 48V C.T. transformer @ 0.5A. many other projects. Supply voltage ONLY $44.50 BEL202 4.5V 9V D.C. 2 for $3.00 X'former BE1l01 3Y,"xS" S1.75 EA. $4.50 ea. FM WIRELESS MIC KIT SB072 3Y2"x6" $1.75 EA. M·34 3"x5" $1.75 EA. lt is not a pack of cigarettes. lt is a CIRCUIT FIT 3"x3Yz" $1.25 EA. new FM wireless mic kit! New de- . .- - - - - - - , - - - . ; . . . . . - - - - - - - . BEL202 3"x4" $1.25 EA. sign PC board fits into a plastic SOLID STATE BEL-OOB 2V4"XS'/z" 51.25 EA . cigarette box (case included). Uses ELE CT RON I C BUZZER a condensor microphone to allow you PUSH-BUTTON SWITCH to have a better response in sound N/Open Contact pick-up. Transmits up to 350 ft.! Mini size1" x 3/." X3/." '-~jColor: Red, White, Blue, Green. Black With an LED indicator to signal the Supply voltage1.5V• 12V 3/$1.00 unit is on :tFMM2 KIT FORM S7.95 Ideal for Alarm or Tone Indicator $1 .50 eac N/Closealso Available • SOCeach , '> LARGE QTY. AVAILABLE


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10 pairs - 5 colors Alligator clips on a 22" long lead. Ideal for any testing. $2.20/pack


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552 Sl.mmlt Ave. Westfield, NJ. 07090 (201) 654-6008

Electricity from the sun. 5 Volt panel 11. amp $50 2.5 Volt panel % amp $40 GIANT 3% inch cell, delivers 1 amp $8.50 Above cell with special motor & prop, runs In sun $10.25

MOTION DETECTOR: Features indude transparSUBSCRIPTION TV EDUCATIONAL KIT ent, optical IC completely assembled on circuit " there'.. TVa..nnel in}'Oll: Jr"whic!1you ",,'tlune toandc.t board with necessary capacitors. Extensive specs • ~ pict... or- . a..nct. Jr, ~ou'" "'~I' ~ and application notesinduded.l $5.00 ~",I~~~=t~~\"~.uer.:=,;:;.~ CRYSTAL~3.579545 MHz 99t '=~~~~~~'~I~:t~ ~~::~~ 6.0 MHz 2.95 ~t~=,;S~~, but sreqweuseofucopund Green,

Computer video monitor chassis 9 Inch, 12 volt used $40 Computer video monitor chassis 12 inch, new $50 Hy Gain CB chassis, trunk mount $9.00

7/I.OO-?~I~~~7~\~~Red, 10/1.00 5=.·~.f~:~~~a.~:: : : : :: : : :: : : :: : : sU~




7 SEG Displays(comp. grade) FREQU EI~~Y7~~r:LER CHIP .3"/95¢-.6"/ 1.45 (specifyann. or cath.) (40 pin), with on boarddividers, AM/ FMRADIO CHIP-{#4408) 2.00 or 3/ 5.00 decoders/drivers. 18.95-specsincluded CompleteAM/FMIC-externallFrequired ZENER DIODE~20V I amp 10/1.00 DIPPED TANTALUMS TV SATELLITE TRANSISTOR .47#135V (I" leads)10/1.00 MRF 901(prime) $4.50 SUPER SUB MINI LmCS UNEAR (I " rad. leads. by Nichicon) UoI 323K 5.00 UoI l303 1.50 lOOO#f SOv (1'100" L X 'h W), 75¢or 10/6.00 UoI 3000 .75 UoIl304 .~ 47~f 25V('Ioo" L XW'W),1 0/$ I.00 ~ ~l~ :~ ~l:n I~ 4OO~f 330V (photoflash or laser circuits)-2/ 1.00 UoI 307 .3S UoI1307E .90 COMPUTER GRADE TWISTLOCKS UoI 306H .95 UoI1310 1.75 3200~f 50V (ideal forpower supplies) 2.00 UoI 308 .90 UoI l391 150 looo~f 5OV-I.00 looo~f 185V-2.00 ~mH I~ ~ l~ l:~ DI~. 001I KV 25 /1. 00 •.1 5OVI 51l.00 UoI317K 500 UoIll108 2.75 HEAT SENSITIVESWITCH-4/I.00 ~~:.15 ~l: U~ self containedunit opens at 150C UoI 32OK·12 1.15 UoIl830 150 9DIGITFLUORESCENTDISPLAYbyNEC ~ill ~ l::i U~ completewith driving circuitry-2.5O ~ ~'1 2:~ ~ t~ EXTRA LOUD 9V BUmR-3/ 2.00 UoI:!4lp.12 12S UoI2Il3 us WALL PLUG ADAPTER-5VDC @I6Oma-1.5O UoI343/i 350 UoI 2907 2.40 6.3VI.2AmpTranslormer-1.75 ~m l:~ ~~ MINI AUDIO TRANSFORMERS-3/1.00 ~ :I l:~ ~ :: 1~ DIGITAL MOTION/UNIT COUNTERMODULE UoI 384 ISS UoI 3065 150 (Fairchild)withlarge 4 digitdisplay &specs-7.00 ~= l:~ ~ ~& l:~ 8035 Microprocessor, 17.00 UoI 390 195 UoI 3071 2.110 INTERFACECHIP-D8243 ~ ~~H 2~ ~~ 16 line 110 extender forall single chip# Ps5.75 UoI 3900 .75 Terms MICRO-MART accepts Visa, MC, and telephone COO'S. Foreign orders $50.00 minimum plus shipping-US funds only. Orders under $10.00 include $2.00 for shipping/handling. All components guaranteed ormoney refunded. Immediate shipping. N.J. residents add5%sales tax. MICflO.MART. 552 SUMMIT AVE., WESTFIELD, N.J. 07090 • (201) 654-6008

------------------------------------------------------------. Govt surplus walky talky, used condo 47-55.4 mc range. Ant. $5 each extra. With data. $25 ea 2 for $45 AN/PRC-6



SEE'IN THE DARKNESS IR viewer, portable, new with choice of one lens...close up, telephoto or gen. purpose. Requires 6 volt DC btry. $250 Parallel ASCII-II Keyboard Unused $50.00 Red LED's large 10/$1 .00 extra on all merchandise




Meshna Inc., PO Box 62, E. Lynn, Mass. 01904




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Ea c h co u rse u e tow ,n cl u d es 0 scec .ct COU' SE' boo k p lu s !,NO cc w e ue v. t o' a to to ! cov -ve Ipn9 '~ a t 1 I h o ur .. Th e re crc ee 1\ co m p 1e 1t" Iy c cc-c .oc te c ' 0 the pc q e s of ,h E' b o ok . an d co ....e ue s CO" be p lot ed o n ony Slan d o rd ca \ ..eue p la ye r

Sl'INTRODUCTION TO MICROPROCESSORS For Nol>Sp<K:lallst s. Course contaim : Defln it lons oAppllcationoElIlIIuation

Tenns oSystemCon¥>onentsoZ5/n

$2995 ° NO



Plexiglass cove as shown


For thestudeniwhohas comp/eted 5 ·1. ~L :l>J)ttWIde an <:Ner-alland prac_·

undefstanding 01 the conct!Jlts 01 Microo Comput.... Programming . Z5 hours.


EPROMS. 2708

1980 I rtc: I

5 6 .75

IK x 8 450 NS .8 FOR 548 .50


2716 5 18 .95 16J((Z K x ltJ4SONS I 2 7 3~ FOR 5!4~ . ~, 49 J2K 14096.-lJ

Master $47 95

Nf GATl't't: 1tOS1 5V J

7'tOI(I't J 7't l $!1 SVI 7911 /1"')


7105 15\1) 1IIM IIV ) 1IOI(1V)

71 Ut1 lV J

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LeedexCorp .



With jumpers and


MINI KITS - YOU HAVE SEEN THESE BEFORE NOW HERE ARE OLD FAVORITE AND NEW ONES TOO. GREAT FOR THAT AFTERNOON HOBBY. See mu sic c o me alive! 3 different lights fli c ker wit h music. One li ght each for , high , mid -rang e and lows. Each individ ually adj ustable and drives up to 300 W. ru ns o n 110 VAC .

supe r high perform an ce FM wire ISS mik e kit ! Transmits a stabl e Ig nal u p to 300 ya rds wi t h exceponal audio Quality by means of its uilt in electret mike . Kit inc ludes 8S8, m ike. on-off switch, antenna, attery and supe r ins t ruct ions . Th is ; the fi nest unit ava ilable .

Complete ki t. M L- 1 $8.95

$14.95 19.95

M-3 Kit M-3 Wired and Tested

Led Bllnky Kit A gre at attentio n getter whi ch alternate ly flashes 2 jumbo LEOs. Use for name bac!lles. b u tton s .

w ar ni ng

panel lights. any1hing! Runs on 3 to 15 volts. Complete kit. BL-1 52.95

ansmi ts up to 300' to Iy FM br oadcast rao. uses any type of ike. Run s on 3 to 9V. Type FM-2 IS added sensit ive mi ke preamp age. ~ - 1 ki t $3.95 FM-2 kit $4.95


fi er w hic h w ill pic k up a

pin drop at 15 feet! Great for monitoring baby's roo m o r as ge nera l purpose amplifier. Full 2 W rm s output. run s on 6 to

15 volts. uses 8-45 ohm speaker. Complete krt. BN-9 55.95


Mad Blaster Kit

r ovic es the basic parts and PC oard required to prov ide a so urce f preci sion ti ming and pulse ene ra tl o n . Uses 555 tim er IC and rc tuces a range o f parts for mo st ming n eed s

Prod uces LOUD ear shattering and atte ntion ge tting siren like sound . Ca n sup ply up to 15 watts of ob nox ious audio. Runs on 6-15 VDC

JT-5 Kit

MS-1 KIt

For wired and t ested cl o c k s add $ 10. 00 t o kit pri c e. SpecIf 12 or 24 hr. format


Car Clock Th e UN ·KIT, only 5 solder connect ion s

He re 's a super looking . rugged and accurate auto cloc k. which 's a snap to bUild and Install Cl o ck movement IS completely assembled - yo u on ly sol d er 3 wires and 2 SWItc hes. tak es about 15 rnmutes' Display is bnght green With aut omatic brightness cont rol ph otocell - ass ures you of a highly readable disp lay . day or mght Comes in a sat in flmsh an od ized alu minum case which can be atta ched 5 cuteren t ways uSing 2 Sided tape Cho ice o f suver. black or gold case (specify)

C an also be u sed as a stabl e ton e encode r. Run s on 5 to 12 vo lts .

Co mplete kit , TD-1

. .

Your old ' Iyorttes I re here I glln. Oyer 7,000 Sold to Olte. a. on e o' th e glng I nd order you rs tod ly!

T ry y o ur hand at bui ldi ng t h e fi n es t look in g c lo ck o n th e mark et . It s satin f in ish a n o d ized a lu mi n u m case look s g re at a n y w here, while si x .4" LED digits provide a h ighly r eadable d isplay . This is a com p let e ki t. no ex t ras ne ed ed , and it o n l y takes 1- 2 hours to ass emble . Your choice o f ca se colo rs: sil ve r , gold , black (specify) . Clock kit, 12/ 24 h o ur , DC-5 $24.95 Cl ock w ith 10 m in. ID t ime r , 12/24 ho ur, DC-1O $29.95 A l a r m c lock , 12 h our o nly, D C-8 $29.95 12V DC car c lock , D C-? $29.95

Super Sleuth A super sensitive ampli-

Tone Decoder A co mplete to ne deco der on a single PC board . Featu res: 4005000 Hz adjusta ble rang e via 20 tu rn po t. voltage reg ulati on . 567 IC. Useful fo r tou chtone burs t detecti on. FSK. etc .

An interest ing ki t , sma ll m ike picks up sou nds and converts t he m to light. Th e lou der the sou nd . t he b rig hter the lig ht. In clu des mike. co nt ro ls up to 300 W, run s on 110 VA C . Co mpiete kit . WL-1 $6 .95

Uniy ersal T im er Kit


CPO-1 Runs on 3-12 Vdc 1 wall out, 1 KHZ coco fo r CPO, A larm. Aud io Oscill ator . Complet e kit $2 .95

Whi sper Light Kit M Wlrele.. Mike Kit



Video Modulator Kit Converts any TV to video rnc mt o r. Supe r stab le. tunable over ch . • -6 . Ru ns o n 515V. accept s std . video signa l . Best u n it o n the ma rket' Complete kit. VD-1 17.15

Color Organ

DC -3 kit. 12 hour fo rmal DC -3 Wired an d tested


$22 .95


Sir en Kit

Cal end ar Al arm Cl ock

Pro d u ces up w a rd and downwa rd wail c ha racteristic of a po lice

The clock that's got it all: 6-.5" LEOs.

Und er Dash Car Clock

12/24 hou r. snoo ze. 24 hour alar m. 4 y ear cale ndar. battery backup. and lots mor e. The super 7001 c hip is used . Size; 5x4 x2 inches. Complete kit. less case (not availab le)

siren. 5 W peak aud io output, runs on 3-15 volts. uses 3-45 ohm speaker. Complete kit, SM-3 $2.95



121204 hour Cloc k In • b• • ullful pin tle clS. ''' ltur . s 6 lumbo RED LEOS. h,gh accur acy ( DO' ''') . easy 3 Wlf. hook u p. d .sp lay blank s ......Ih Ig n illon . and s upe r ,n str uchons O pllona l d l m m~r . lu om , l,ca lly

ad,U'" dIsp lay to amblei'll Itg h l le ...,,1 DC - ' .' cl oc k wllh mi g b rac ke t 0 10.' -1 dimmer ad a pter

Vid eo Terminal



A co mp lelely seu-ccete-eec sla nd alo ne vreec l.rm...~ .1 car d R ~u lres o nly an AS C II keyboard and TV

se t 10 become I co mp lete term ,nal unu Fealu res are s,ngle 5V su pply Xl Al co ntrolled sync an d baud rates flo 96001 ca mpl elf' cem pu ler and keyboa rd CO'llrO I 01 cu rso r Panl y erro r cce u o r and d'splay Accepts and g e" er ates sen al ASC II p iuS para Uel ll;eybOard Input Th e 6-416 ,s&4 c har by 1I5lones w llh sc ro llI ng up per and JOWlI e r c ase ( o ptl o nal l a nd has RS·232 II"ld 20 ml loo p Interl ac n on bo a rd K ,ls In c lud e sockels ..n d coreerete doc umental Ion RE 6-416 ter m,nal c ard klt l ldd S60 00 lor Wired uru tJ Low er C ase Op i io n Pcw er Supply R~ Modulato r k It

;-- - - - - - - --r-- - - - - - - - ---j TTL

LINEAR 01 24 ao

$ .35 $1.SO

1~ ..

55 56 65 66




67 41

$ .40 $ .65 $ .50 $ .50 $1.35

74S00 7447 7475 7490 74196

$ .50 $2.95 $2.95

"Win II :: t1~ 1-=-=--



t1.3S t1.15


READOUTS ' NO 359 -4 ~ C C 11 .00 "NO ~115 1 0 S-C A 1.00 AAN 72/ HP7730 33 ~ C A 1.00 iP 11551 43 ~C A 2.00

TRANSISTORS !N3904 NPN ' ~N39OG PNP !N4403 PNP !N44 10 NPN ~N4i 1 6 FET ~ N S40 1 PNP

>NOOn m3771 NPN Sohcon ~N S17'



Jtowet Tab PH P 0'N Io4Pf 102I2NS4&-4 "'IPN 39(W Ty pe PNP 390e Type

1N305S 2N2&4a UJ T

Crystals 3.579545 MHZ 10.00000 MHZ $1.50 5246800 MHZ

Switche s

MinI toggle SPDT Red Pushbuttons N,O.

$1.00 3/$1.00

15/$1 .00 151$1.00

3 " leads . 8 ohm . good lor small tone speake rs. alarm clocks , etc 5 to< $1.00


l1C90 10116 ma 7208 - - - - - - - . , 7207A 7216D CMOS 7107C 011 _ .10 5314 5375AS/G 7001


Resistor AII't Assort ment of Popul ar values - ~~ watt . Cut lead fo r PC moun ti ng . W' center. y," leads. bag of 300 o r more .



t1s.oo $ 1.25 $17.50 $ 5.50 $21.00 $12.50 $ 2.95 $ 2.95 $ 6.50

W,th '1'110Ind SpKS 6 Ho le Bal un Beads

8 PIn 14 Pin 16 Pin 24 Pin 28 Pm 40 Pin

Sock ets 10/$2 .00 10/$2 .00 10/$2.00 4/$2 .00 4/$2.00 3/52 .00

Dio des 5.1 V Zener 20/51.00 1N914 Type 50/$1.00 1KV 2Amp 8/$1 .00 100V 1Amp 15/$1.00


1 10 VAC plug 85 vdc @ 20 mA $1.00 16 . vee @ 160mA $2.50 12 YIC @ 250mA $3.00

S1I t tS


1 14.'5


600 MHz PRESCALER Ex t en d th e ra n g e of yo u r cou n ter to 600 M H z . Wo r k s w it h all count ers . L ess than 150 m v sen sit ivity . sp ec ify 10 o r - 10 0 Wired, t est ed , PS-1B Ki t , PS-1B

$59.95 $4 4 .95

Appro x 2 '1. ~ dlam Round ty pe for redrcs. mike etc

3 tor $2.00 t-=-===-------....L.=="i"''--------'==--l

AC Outlet

Panel Moun t w it h Lead s


f-:=====-------'---------t CAPACITORS

--1 15111.00 5/$1 .00


M 1lI8peat...



Audio Prescaler Make hig h resolution audio measur ments. g reat for mus ic al instrument tu ni ng . PL ton es. etc . Multi plies audio UP in fr equ enc y. selectable x 10 o r x100 . gives .01 HZ resol ution wi th 1 sec . gate tim e! Hi gh sens iti vity of 25 mv , 1 meg input z and built-in filt erin g gives g rea t per for manc e. Run s on 9V battery. all C MOS . PS- 2 kit $29.95 $39.95 PS-2 wired

$1.50 $5.00 $5.00

AC Ada ple,.

I~ :gg I---------+----c:;;;;-.:==;------i ~~:r~~~s, a ll Earphones $1.25 101~2:~

458 ,900 ,9 104

$27 .15 kll S2.SO

Ad d $1000 Assy and Test

DlppeclEpo-,:y 15~ 25VII$1.oo 1 a J'F 25Y 111 1.00 22,.F 25V 1/11.00

ALU MINUM EIKlrolyhC 1000 u~ 16 V Ra d,a l $.50 500 uF 20V A ,IIl la l $.50 150 u F 16V Allal 5/$1 .00 10 u F 15V Rad ,aI 10/ S1.oo

DIS K CERAMIC 01 16V d Isk :G / $1 .00


100pF 0411 6V

~: ~ ::


:G/ 11.oo 201$1.00

Ceramic IF Flit .... Mini cera mk: Alter. 7 KHz

B. W. 455KHz 25K 20 Turn Trim Pol $1.00 1K 20 Tum Tom Pot $ .50

Crystll Microphone Small 1" dia me ter y." th ic k cr ysta l mike cartridge $.75


. OP·AMP Special SI-FET LF 13741- Direct pin for pin 741compatible. but 500.000MEG inp ut z, super low 50 pa inp ut cu rrent. low power drain .


50 tor only



10 for

78MG 51.25 7812 $1.00 79MG $1.25 7815 $1.00 723 $.50 7905 $1.25 309K $1.15 7912 $1.25 :;:::: I - - -- - - - - - +- ---'-'----=---:--.....J'---.,---=== C on MCtO=rl - --j Pamll-t 7805 $1.00 7915 $1.25 41$1.00 ASSI o f cec....s d ' sc c aps IInl r eSISlo r s 25 A MP ~~i~~ec~~I~I~~t~c~~~~ f---:..:..;===:-::7:-::'-==----r-----;:::-:=~:__:,:-:_=:_:,:.=---t t r an Slsl o rs dI odes MI C A caps et c $1.50 Shrink Tubing Nubs Mini TO·92 Hilt Sinks sm ~ 1100 pe l $1.00 Ig , ~ 1300 pe l S2.SO pri ce .15 ea . 100V Bridge 3111.00 Nice precut pees of shrink size : t - x '.4" Thermalloy Br and 5 tor $1.00 31$1.00 shrink to '..... Greet for spli ces. 501$1.00 To · 220 Heat Sinks 3 tor $1.00 $ 1. 5 0 ea c h Leds - your choice , ple ase spe cify 311.00 • Mini Red. Jumbo Red. HIgh Intensity Red. Illuminator Red 8/$1 O pt o Is o lat ors - 4 N 28 t ype $ .5 0 ea . uo M in i Yellow. Jum bo Yellow, J umbo G ree n 6/$1 Min i-B r id ge 50V OOIS2.SO Opto ReflBc tors - Phot o diode + LED $1.00 ea. OOIS2.SO 1 AMP Varae tOf"l Mole. Pins CD S Photocell. . S.IO Mo toro la MV 2209 30 PF No mi nal cap 20-80 P F - Tun abl e rang e MoIex already prec ut in length of 7. Perfect Resistan ce varies with ligh t. 250 ohm s to 2 for $1.00 .SO _ Of 3IS1.00 """00

151$1.00 15/$1 .00

Coa x Co nn ector Ch assis mount BNC typ e $1.00

for 14 pin 5QCkets , 20.trt


tor $1.00

over 3 meg

3 for $1.00





;: CD





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S N704N SN 741SN SN74}fi N SN 70 9N SN7qoN SN 7412N SN141JN SN7415N SN7416N SN 7419N SNl490N SN74lJIN



C D4011

5N' . 7JN


."." ."." ." ." ...."

C D40 19

CD4Q20 CD4021 C D4022 C D4023 C""""' CD<02S CD402li C D4021


5N7470N SN74nN



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1."9 1...9


2." 1.35 1.19 1.19


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2." 1... 1... 1.95 1.25 ~90



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l.3" 1.3, 1.35

1." 1.35 1.35 1.35 1.25 1." 1." 1." 1." 1.25 1."



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1.35 1.35 1." 1.25 1." 1.25 1." 1." 1." 1.00 1... '.25 ' .00 1."


I. " I." '.00 '.00 '.95

,." ' .00


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1.35 1.35 1.35 1.35 1.35

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. .

..35 ., .35 . IS


1." .35 .35 .35 .35 .35 .35 .35 .35


.35 1.05 1.05


74 L SOOTT L .29

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.29 .54 .54 .71 .54


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X C556 R X CS56G X C5S6Y XC556C X C22 R


.200" .200" .200" .200" .200" .200"

red g ree n ye llow

cle ar

red g ree n .200" ye llow .170" red





14. 95

7." 1." .. 25



CMOS PredslonTImer


24.95 19.95 7.50 19.95 6.95

CMOS LED Slol>w11chm mer

Osdlltoreontrorler SMo _de Count" Clod; Genemor




NMOS READ ONLY MEMORIES 128X9 X 7 ASCII Shil1ed _ Greek 128X 9 X 7 t.b1tI Symbol & PIctures 128X 9 X 7 Alp'" ContmlCI1.I' Goo

MCM6571 MCM6574 MCM6575

13.50 13.50 13.50 2.49 4.49 1.75 19.95 11.95 3.95 17.50 3.75 10.95 1' 95 3.95.

CD40 7S C D40lIl CD4002 CD4O'l3 C""""



1.19 1" .95 1". 95 1" .95



... ,.... .IS

CD4". C D4' "



1." 1." 2." 1.29 1."


MV" X C209 R XC209G X e209Y X C 526 R X C526G X C52fiY XC526C

MAN" 20 MAN 3630 MAN.... MAN 4610 MAN 4640 MAN ..710 MAN"730 MAN"7"0 MAN 4810 MAN4S40 MAN 6610

MAN .... MAhI&710





L M75450 N 7545ICN 75452C N 75453CN 7S454CN 7S491CN 7S492CN 75493N 754MCN RC41J6 RC4l51 RC4194 RC4195 7" L S I39 1" L S 151 74 L S I5S '''LSI57 7" L S I60 , .. LSHil '" L S1 62 7" LS I6] ''' L S I64 7" L S I 75 7" LS1I1 7" L S I90 7" LS191 7" L S I92 7" L S I93 7" L S I94 7" L S I95 7" L..S253 7" LS2S7 74LS258 7" LS260 74L5279 14LS367 7"L536a 74LS670




Common Anode-ormge Common CIttlodt-mngr Common Moot·red Common Anode·red ± 1 Common CltI'IOde -rtd CommonAnod.-yel1Ow

.300 .•00 .' 00 .' 00 '00

(;(NnmonCltI'Iodt-yrIlow :t

1." 1.25 ...... ......... ...... ..... ......... ...... ........ ......


... ..see.... .........

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Common Anodt-oranot-D.D. 1


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X C lll R . 190" re d .190" g reen :190" ye llow

x c i nc .190" etea r






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.32 .35 .37

.37 .31 .00








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1.10 1.65

. 1.00 1...





. 31



1.25 1...

... ..... ... ...... 1." 9





.110 .2S0 .351 .3S7 .




4 x 7sg!. Digit-RHDP ...7 S;1. DIgIH HDP Dwrnngtc:NrxtIf(::t-1) " x7Sg1 .Diglt-Kt:xldeci1Nl

.300 .100 .100


1... 19.95 IU5 15.00





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M CI 408 L7 ' .95 MC1401U MCl"J9 L 2." M CJQ22P 2.95 MC306 1P fv1C4016(14416)7.5O M C4024 P MC4040P MCI044 P

.......". ....."".






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I" pi n 16 p in 11 p in 24 p in 21 p in 36 p in 40 p in





."." ..,




1. 15




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.99 .99 XR567CT 1.25 XR1310P U 5 XRI 468CN 3.85 XRI 488 1.95 XRl 4a9 1.95

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""" ""M 2H232I

8 10 14 16 l'








.13 .31


.70 .11


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MPSAOS MPSAOO 11597 11598


1.01 1.35 1." 1.53 1... 2."

1. 19



I." 2.19 2.29

2N918 ~N22 1VA 2H2221A 2H2222A ptl!2222P ln tic 2N2369A MPS2369

1.23 1.1"


I." 1...



"11.00 " /1.00 "" .00 411.00 " 1100 "11.00 " " .00

"'1 .00 " 11.00


21 28

2a 2a 28 611.00

!iI1.OO 511.00 1211.00


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1.05 1.05 1.05 1.05 1.15

1." 1." 1." 1... 1." 2."9







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3.3k 8 <'k 72..




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150kIJ )9DHl,l

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6/1.00 1.75


2M3398 PN3567 PNl568



4/1.00 ~/1.00

MPS3638A MPS3102




MPS37Q04 2H3705 MPS3705 2H37Ofj MPS3106 2N3707 2tr13711 2N3n otA

111 .00 4/1.00 5/1.00 " 11.00 " 11.00

511.00 1.25

2H3nSA 2H3n2


2N3823 2N





1.1M ).)1,1




1.75 1.75


H ... 50





3)0( 810K

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1.' U

<'.2104 5.6104

ASST. 8R Includes Resistor Assortments 1-7 (350 pes.)

1.75 $9.95 ea.

50 pcs

$ 10 .00 Min. Order - U.S. Fun ds On ly Sp«: Sh Hts - 25 li' Clli f. Reside nts Ad d 6 % Sales Tu 1980 Cat l log Av. i1l b le - Send 41; sump Postl ge -Ad d 5% plus $l lnsur l nce l ifd esir~l

1." 1."



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12 .12 .12 .12





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1.5104 1 9104

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12A@ YN 12A €t 'lOfN


50 PCS

l2n .OO 1211.00 1011.00 1011.00 1011,00 611.00

20:1PfV1 AMP 400 PN 1 AMP 1H4005 600 PN 1 AMP l H4006 am PN 1 AMP l N ~ OO4

35A4l tnN 1.1A4i' XtN



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68 DkM I<' OHU 100 Dk l,l lao DH'" <'20 Ok M 1100 11104



' .95

100H.... 17 OHM




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~4002 '"fOllTSpN~ AMP

15A ~ 4fXN


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set 1.50 4.25 3.20 2.99 1.25 1.25 3.95 1.45 3.60 2.05 .75 1.15 1.47

15" .00 1211,00

<'8 21 21 28

2a 28

28 1.60

1.10 1.70 1,80



MOA tao-3

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p tnWW p ln W W pl n W W p in WW p ln W W 20 p in WW 22 p lnWW 24p lnWW Zl pl n WW J6 pl nWW 4D p lnWW

XR2242CP XR2284 XR2556 XR2567 XR3403 XFWI36 XFW151 XR41 94 XFW2Q2 XFW212 XR45S8 XFW739 XR4741

JE2206KS 19.95 XRI800 3.20 XR22Q6 4.4lI XR2207 3.85 XR2208 5.20 XR22Q9 1.75 XR221 1 5.25 XR2212 4.35 XR224l1 3.45


f---'-= =-= .,.:::,:..,,=--.::::....-- .:::=-I :~;: WIR E WRAP SOCKETS (GOL D) L EV EL # 3


$8.40 4.40 ' .4lI 1.55 1.50






.seo 630 .eoo


50-100 .1' .11 .20 .21 .30 .35

. l9



Common Anode·red Common Anode-red ± 1 Common Anodt-red COIl1lnon CIItIodI·rtd:!: 1 Common CdlodI-fid Common CoIthodt-red CommDl'l Clltlodl Common Cathode ± 1 CommOti cathode Common Ca1hodt(FhlD5OO) Common Anode (FHD510) Common AnoOr-1'Id Common Anode·rtd Common Clthodt I'Id

LOW PROFILE (TI N) SOCKETS 1·" .11 .20 .22 .29







p in p in pi n pin pi n 21 p in 36 p in 40 p in

HDSP-3-400 HDSP-S403 5012-7300 "",-","

300 .300 .300

Common Anode·red Common CiItlodt -red




Common Anoc!t·red Common Cathode-rid Common Anode·red ± 1 Common Clltlode· red

FhlD503 FND507


.sse .. ..sse.sse.. ........ ... .seo ....... PRI~


Common ClIhocIt-red j; 1


M M572S MM5731 ~ O M.... 2.00 D M1865 1.00 D MaII7 .IS O M.... .IS 9]7" 1-509 · L E D d r iv e r 1.50 M M"'"


MAH6130 MAN6740 MAN 67SO MAN 6760 MAN6780 Dl71l1 Dl704 Dl 707 Dl na DL741 Dl 746 Dl147 Dl 7" 9 DL7SO DLl3 B fND70 FND3S8

25.00/set 13. 95 SN 76-4n SOUND GENERATOR Geoemes Complex Sounds Low Power- Programmable

IN F ij A - R E D L E D V." xV. "x l/16" f hl t 'lS '

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' /Sl '/Sl ' ISI ' /Sl

xc mo x c inv

veucw ' ISI


CA3OI2N 2.00 CA3OI3N 1.00 CA308I5N .IS CAJOI9N C AjUn 1." CAJI40T 1.25 CAlI50T 1." CA3401N .59 CA3500N

I p in 14 pi n 16 p in 18 p in 20 p in 22 p in 24 p i n 21 p in 15 pin 40 p in


. 000B

Common AnOOt-ytIlOw Common CllhodI-ytIlOw Common AI\odt.D1lfIOt Commol'1 AnodI-orlngt j; 1

2.15 ' .25 2." 1.35 1.30 ' .25 ' .25 1." 2.00


.300 .300 .300 .300 .300 .300 .300 .300



L M 710N L M 711N L M 723 N / H L M 7.13N 1.00 L M 739N 1.19 L M 7" I C N / H .35 L M7" l-l.. N .39 L M 7" 7N /H L M 748 N / H .39 L M 1310 N 1." L M 1458CN/ H .59 M C l4a IN 1." MC I4a9 N 1.95 L M I496N L MI 556V 1." MC1741 SCP 3.00 L M21l1N 1." L M290I N 2." L M lO5J N 1." L M3065N 1.", LM3900N(3401) .S9 L M 3905N 1... LMl909N 1." MCSSSlIV .59

.085" r ed . 125" .125" . 125" .115" . 1as " . 185" . Ias "

""~ 2."


Common Anodt-orU91


1... 1."

.300 .125


Common ~-orMI9f:-D .D , Common CIll'lodt'orll1Q' .: 1 Common Anodt-onng. Common ClthOdl!-orangt Common Anodt-rId ·D D.

' '' C922


5 x7 Dot Mltllx· ~


2.00 2."


HT .270

Common AnodI-grwn Common Anode ·yeIow Common Anode·rlC!


7"CI63 7"CI64 7"e173 '''C I 92 ' ''CI93 ' '' C I95


POUIlITY Common Anode·red



2."9 2." ')



' ISI 'ISI ' /Sl 'IS I ' lSI 'IS I '/Sl 'ISI

Common CllhOdt·red

MAN"'" MAN..., MAN.... MAN....


.. .... .. .. .. ... .. ... $ 39 9.95 .. .. ,,, _$499.95


MAN ..



.35 .35 .35 .35


1." 1."


LI NEAR L M 340K -18 L M340K· 2.. L M340T --5 L M 340T -6 L M 340T ..a L M l4OT · 12 L M 340T · 15 L M 340T -18 L M340T -24 L M lSa N L M370N L M373 N L M3 n N L M3aON L M lIOC N L MlII N L M3I2 N NESOIN NE51 0A NE529A N E5]IHfV NESJ6 T





.10 .35 .IS 1.00 .00

1.49 1.49



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2.1 5

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C04510 C04511

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A Y +9l oo AV....,.. AV....... AY--5-2JJ16


C D40 70 CD4071


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5N74191N 5 N 74192N SN 7419J N 5N74194N SN7419SN SN7<4196N SN 14191N S N 14198 N S N 14l99 N SN74S2QO SN7425I N SN74279 N SN 742t3 N SN74284 N SN 74285N SN14365 N S N74366 N S N1..367N SN7"36a N SN1"390N SN 1" 393N



1." 1." 1... ' .00 1.25 1.00 1.00

5N741I4N SN 741ISN 5 N 14186N 5 N 74111N S N l 419(1N 1."




SN l 41&2N

MCI4409 MC14otl0 MCI....l1 MCI4419 MCl.... 33 MC l"SQ6 MCl"S07 MCl"562 MCI45&]


...... ........

5N 74160N 5N 74161N 5N 74162N 5N741 63N 5 N 14164N 5N74165N 5N74166N 5N74161N 5N7411ON S Nl41nN SN74173N SN741J.iN 5 N 141l$N 5N14 116N SN 1·UnN 5N14 119N 5N7411ON 5N 74111N





7400 TTL


.39 .39 .39 .39 _E

DRS 19 1.00 5/1.00 5/1.00 311.00 4/1.00 4/1.00

5/1.00 5/1.00 511.00 5/1.00 5/1.00

5/1.00 511.00 511.00 511.00 511.00 .65 1.00 225 1.00 51100

:s~"~=~ 1£l = .001" f 03 .OOC7,.f

.04 .04 04 04 . 04

.03 03 .035

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022m! .047m! .1m! 22ml



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2H''''' 2N390S

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3/1.00 6/1.00 4/ 1.00 411.00

4/1.00 4/1. 00

4/1.00 4/1,00 511.00 " 11.00

4/1.00 411.00

" /1.00 511,00 5/1.00 511,00

511 .00 511,00 311.00



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The Incredible

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S7.50 7 50 5 00

. " $139.95 ' is


"" "M5Z3OH



$1.( 9

''',",,' "'" """ ....."'"

,,," 175 I ."

""", S."

Mete r consists of a sensor cel l att ached to a com pact (3" x 3'4" x 3") meter ing unit. Can be hand-held or placed directly on surface fo r measuring. Can be used remotely , while conn ected to a met er housing by a 4-foot ext ension cord . Two model s available - one for long wave and one for short wave ult raviolet. Readings are in microwatts per square centimet er. Weight : 1 lb. Completely assemb led (includes sensor cell, reduct ion scree n, extension cord , contrast filter and certification report.)

J -221

LONG WAVE (300nm-400 nm)

J -225 SHORT WAVE (200nm -280nm)





"".,., "0"


'"" '" " 4.515

2SZ9 2>32 3341 7.(l S670


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.(x.( RIO'ner

' is

7." lU 5



Filt (TnSutt)



Function Generator Kit Provides 3 bas ic w.vef o rms : sin e, tri an gle .nd sq uar e wav e. Freq . ra nge fr om 1 Hzto 100K Hz . Output am p litude from 0 vo lts t o oyer 6 volts (peak to pe ak) . Uses. 12V supply or a :t6 V split sup · pl y . Incl u des ch ip, P.C. Board , com-p onents & inst ru ctions.

• Erases 270S, 2716, 1702A, 5203Q. 5204Q. et c.

• Erases up to 4 chips with in 20 minutes • Mainta ins constant exposure distance of one inch • Special cond uctive foam liner eliminates static bu ild-up • Built-in safety loc k to prevent UV exposure • Compact - on ly 7-5/S " x 2-7/S" x 2" • Com plet e with hold ing tray for 4 chips

$69.95 JE2206B


" is ' is .((1 ,00


1702A 27161NTEl TMS2516 (2716) TMS2>32

fA-Ma S EPROM 16K' EPROM ' Rtqlllrts SInQII . 5V powersupply EPROM '!<X8 EPROM l&K" EPROM 27161.1 "RtqUlres 3 YO~ ", -5V, . SV, + 12V




DUII ~BIl Subc

DUll 250 Sbtic DlW2«<lBIlStIlIc QlWISO lid Stme


17 5

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Dull 100 Bot Stlbc OUJI604 IktAc:cumulltor 500/512 8lt Dynamic 102.([)yNlTlic Htx 32 BItSti lle 0uII1 32 BItStille 512 Su bc l 02.( OynIfnle

IllM51 0H MM5016H 2504T 25111 ' 252Z

A-Y·S·l0 13

Jumbo 6-Digit Clock Kit


"."" """ "''' "' "'" ,.... " ,.",

- - - -- - UA.r s - - -- - -

UVS-11 E

' is 7iS


2S2S $260.00 "" ' SZ7

EPROM Erasing Lamp

'" "" ""


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6301-1(7611) 6330-1(1602) 112523 825115 1125123 1.(186 7.(1811 7,(52117

"''' 102.(

* * Hou rs e"s lly

viewAb le t o 30 feet .. Si mul at ed wa l n ut cue

10 95

* 115VA C

,.. -

_Du. 1 ..nlOn-switch lng co nt rol fo r l n door/outdoor or du al monito ring -Co nt in uou s LED ,S" ht , display - Rang. : ·4 0 °F to 199"F / ·4 0~ to100OC : ::tc ~~arc~:a;~:n7,c.7; i~~ 1 C.lsius read ing -8 1m . wa ln ut ca.. - AC wa ll ada pt.r inc!. - SIze : 3- 1 /4" H x 6 ·5 /S " W x 1 ·3 / S "O


DESIGNERS'SERIES Blank Desk-Top Electronic Enclosures

op eratio n


• ~~Sh P~:::ti~ ~~:filmb~~~~



finish. • Sliding relr!bottom pl nelfor service and component IC' cessibility. • Top / bottom pl nels.OBO thk alum. Alodine type 1200 finish (~old t int colorl for best PIlOt Idhesion Ifter modifation. • Vented top I nd bottom panels for cooling efficiency.

$29 .95 cs -



_ Bright .3 00 ht . com m. cat h ode di sp lay -U H S MM53 1 4 clock. chip - Switch es for ho urs, m in ute s a nd h o ld mod es _ Hrs. eas ily viewable to 20 ft . - S im 'Jlated wal n ut ca.. -11 5 VAC ope rat ion - 12 or 24 h r. op eratio n -I nc!. all componen ts , cue & wa ll t ra n sfo rmer - Size : 6"" x 3 ·1 / S " x 1 " "



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* 12 or 24 h o ur o p e on * Inclu d es all co mp o nent s, case and wa ll tra nsformer * Size: ,IN x 3\11 x 1:¥4

Expan d your 4K T RS-8O Syst .m to 16 K. Kit co mes comp lete with : Rams) 250NS

'*8 each UPD416-1 (16K Dyn amic * Docum.nt.tion fo r con....rsion





TRS-80 16K Conversion Kit

'" ' 95 ,,,




$59.95 "." TRS-16K JE610 ASCII ,." Encoded Keyboard Kit

* F our .6Xl" h t . • n d

tw o .3OO" h t . com m on ano dtt d ispl AYS U ses MMU14 cloc k ch Ip .. Sw itches for h o u r s, m inu t es . nd h o ld f u nctio ns


Oab Trl I IIllISAII ....... . , •• . fltClul ncy·SMt KIyng . lul-(f ~plfx (hllf-dupiD.

...nnt. Ill DaIl Rlt• . •• . . •• ••• .300BlIlCI Dati flmut •••••• , . • . . . • . • • . Asynctvonous Sf,. (l'IIurn10mal1.lht1 reql.llrtll betwWl Nch Cl\I.racttr) . 11K "'" CIlllWlllf~. .It • . . .2025 Hzfor spua , 2225 Hllof mart Trl ltSmlI CIII...l f,..._IIS .. S.-cth~ lOW'lnorrNll) .1 07Ospact . 1270 mart; HIgIl ... 025 1(Ob. 2225 mart Afttln St IlSltlYlty . • • . . • • .. . • - 46 l1bm IWMtaity covpleoll Tr' "l1lllll , 1 - 15 dbm nominll, Adll.l suble 110m - 6 dbm to ~ 20 lI bm RlCtIYlFrt ~' IlCYTol .rl nct . . •Frl qutn cY 111,l tnC:l ll.Itoml! ICI,lIy alllusts to ~ lo r09lrlllQt1 bttwWI 1800HlIlnll2400Hz. DIgital Oltlllltl l1l ct •. " •••• . EIA RS·232C 01 20 rnA curnnt loop (rte:tlVer IS optotsollWd andnon·pollr) I"owtf Fl4u,lrin mlJlCs • ..••• . . . •120 VAG, MglI pNM , 10 WIttS Ptlysical •• ••••• ••• •••• •• ••• •AIl compontnts mount on I SIngle 5' by ~ ' pm tedClrt\llt bolrll AlCOtIW1t/1I:sltlCtulltd RerQLllm a YOM, AudIO Osol.ltor, Freqlltl'CV Coutlter and/OrOso/loseopelo Il9I

" is

Tmute ffi Optn CoIltclor ffi Open Collector

S12 '56 '02'

~ -

Kit Only

T1III ... ..,•• l l3 is ~ 04rKC)rdlng I1Itito anlI from IlIdIotlplwr!tloYt Cl1tiaIIspeed rtqlI\rImInts lorttIIrecordtrlnd IIISabllto c:om rrll,ll'llCatl(llrldly anochIr molIem anlI t,mwtII for telePftOnt " lUl'Ilmlng.' nI C(Ir1"IfTlijnicltlonS In allMon , CISIf"04cntlC11ac1~stments InlIlSbuoIt .. ttl non1WtoSlOll. tNt*t1VlUblt


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103"1~"!!t~~~ ....

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Ttistate Bopolu Open C BipcNr


'2XS '096




The JE610 ASCII Keyboard Kit can be interfaced into

most any computer system. The kit ce rnes complete with an industrial grade keyboard switch assembly (62-keys), IC's, sockets, connector, electronic components and a duuhle-slded printed wiring board. The keyboard assembly requires +5V @ 150mA and -12V @ lOrnA for operation. Features: 60 keys generate the full 128 characters, upper and lower case ASCII set. Fully buffered. Two user-define keys provided for custom applications. Caps lock for upper-case-only alpha charact ers. Utilizes a 2376 (40-pin) encoder read-only memory chip. Outputs directly compatible with TTL/ OTL or MOS logic arrays. Easy interfacing with a16-pin dip or l8 ·pin edge connector.


(Case not included)


Desk-Top Enclosure for JE610 ASCII Encoded Keyboard Kit Compact d . sk -top . nclosu r. : Color-coordinat ed d esign er's ca w with light t an alum inum pan els a nd molded end pieces in mocha brown. Includes mounting hardwar e . Size : 3 %"H X 14 %''W X 8 "'''0 .




(Valu e $ 129 .90) . . . . •. . . . . . . • .. . $124.95

JE600 Hexadecimal Encoder Kit FUL L 8-e1T LATCHED OUTPUT 19·KEY KEYBOARO

6-Digit Clock Kit $19.95 Regulated Power Supply Uses LM30 9 K. Heat sink . ,~ provided . PC bo ard con- struction. Provides a sol id 1 amp @ 5 vo lts . Can supp ly up to . 5V, . 9V and . 12V wit h JE205 Ada pte r. Inclu des compo nent s, ha rdware and inst ruct io ns. Size : 3 y," x 5" x 2"H


$14.95 ADAPTER BOARD - Adapts to JE200 ±5V, ±9V and ±12V


DTE-8 DT E-11 DTE-14

8.00" 10,65" 14.00"

$29.95 $32.95 $34.95


speed sWitching XMF R. Short circuit pro tec tion . PC bo ard con struction. Piggy·b ac k to J E 200 board . Size : 3 y," x 2" x 9 / l6"H


Pa nel Width

$ 10 .00 Min. Ord er - U.S . Funds Onl y Spec Sh ..ts- 25; Calif . Resid ents Add 6 " Sal es Tax 1980 Catalog Avail ab le - Se nd 41; sta mp Po st age -AddS" plu s S1Insur .nc. (if d esired)

DC/ DC co nver ter wit h +5V input. To rio dal h i-


Enclosure Mod e l No .





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2.95 8.85 1.10 1.10 US9 1.79 .98 98 .98

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CA3Q.48TI l l.4J053N CA3059N CA3060N GA3062N LM306 5N GA3080N CA306 1N GA3082N GA3083N GA3086N CA3069 N GA3096N CA309 7N CA3130T GA3140T GA3146N GA3160T CA31S1ON CA3401N M~ 23 N

MC3"6ON SG3S2" N CA3600N LMJ 900 N LM3905 N LM3909 N AC413 1N RC4136N RC41S1N AC4 194 AC4 185 ULN2001 ULN2003 SN7S4!>ON SN7S451 N SN7S452N $N75453N SN7~ ~N

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' " . .. . . 462500

po:d,a- _ ror. ~l'JlOdIIl;_cnrJ

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1.95 1.70 2.95


3 TIm .. Mo,.. Powerful TMn ALA

WE.1U1 U I TUTEI ••• •. •.. . . . •• •. ••••• •. . . Ultft


2.95 1.99 1." 1." 1."



800 & 400




,... MSlC••••

1II6.esI . ,•••

.... ....... .. s.c-~ '" ~ s.c:-~1OI ~Ctltc


AM/FMste<eo SIITOlI'd5i11d fils veu body

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(k commodore

PET Lcf:p.s $775.00


You W8M it!

2a3H 6KI 2OQ1·3:2Q ••..•.••••. 2a31·3:lQ!IIIII . .•.


2'OD1-11101 . . ••• ••

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202310·( "'. . , . . ".,. .. IIS.OO 2Oll0~..,.Dltko- . 1250-00

7S00 Plt llllEUc. ..••. 125000 I(UllIEEECItIle , . . . 125000 DIet 2OlZIO-CdDat.... ""'- •• m.Dll



Ariin:ltanl tran:!lator

01word:! and

~~:l~~ :~.


Compatible MocIeI FOO-120-8 0 . • . . • .• . . . . . . .. .. " 29 ,00 PERSCI Model 277 Dual 1195.00 WANGOISIEMENS 5""" 0nYe 290 .00 I.4Pl 852 S ," M DuaL•.•• . . .. • . . . . . . . • . . 395 .00 WANGO/SIEI.4ENS282 Dual 5\40" . • . . 395 .00 WANGO/SIEI.4ENS 82 . . . . . . . • . .• . 2ltO.OO


guages pl u:! a four lunchon calculator plus inlormahon


e. bar. and wine guide. etc.


c nbI_

MONITORS 5an yo 9" . . • . .. . • . • • • ; • • • $ 169 ,95


l eedeJil1Z" • • • . •••.• •• . .•• 139 .95 Mot or ol.. 12 ". Resol u tion . 22 MHz . OEM ModtN . M3000-340 ... . .. .. . ••• 2 19 .00 Zenit h 13" Cob- Wonitor. . . 4GG.00 MQA.13" Co&orlV .. •. ••. . 349.00 VAM P 19- CoIor Monrt or .. . 57 5.00 VAM P 1 5~ CoIor Monitor •.. 449.00 ~CONTININTAL


IWIIJOD I DIgItal Capacrtance Meter,•.. 275,00 _ Ul Tn-Mode ~klr 29500 _ LII·1 40_ Loo< MoRtor .• .• 585.00 _ LII·t Loo< """'klr 6000 _ LII·1 Loo< M""" 147.00 _1I81S_F1r<blnGenoaklr lll6.00 I*150D1 UniwfsaI Cclnter·Tmer 36000

~1O' 1650MHIFrelJl'MCYC<u'lt!r 38500 MAX-lIDO 100MHzPoruibIe Freq.Jercy Ccu1ler ....• . .. ....••.•..••.••••• •••• . . 14900 PS-500 sao 111Hz Decade Presc:aIer.• •. .• . 7000 MAX·51 SO MHz H~ F~ Colrief

................................. noo

JUS . 4115 1500



Shugart 8001801 R 8" . . . . . .. ..••. • • . . " 7S ,00

San yo 15" . • • . .•••. .•• . ••• 279 .00

'" "" "" ""

Superior Col or, Mu sic, Sou nd and Gra ph ics - and a Powerful Exte nded Basic - All Built In. TI 99/4 Console only availabte for $698.90 .

I.4Pl B5 1·5V.~. 40 trado;s •. • •. • . • . . . •• 279 ,00 Shugart 35 tracks . . . 285,00



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'''' '''' '''' "" ""

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11MsyWm. WI~. IIdIln:krllo6 4*\l aystaI !lqCCU'lllf.pU"*"ahrln:llCN.

[iiI _. . - -

~~~:6\:~~~~~~ $119.95


. . . . ..,111; CRAIG MODUL ES AVAILABLE FROM $2.95

The the rmostat that uses mIcroprocessor


tec hnology 10 save fuel and money.



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• No installat ion • Protect s a whol e hou se


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Compa re the co st: TPl's tempera ture controUer is the lowest pric ed elec tronic thermosta t on the market.

• Exit and entry delay • BaNery back-u p

MU·550 550 MHzH~ F~ COI.ri« .••.•. ......••. •.••••.•.. .••. ••.. 165,00


.........1 PlAse Gentrator .•.•••..• •. 13500 _ 1~ 1 DogQI 1IAs« 8300


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2800 77.00

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. ""LTH LTC-l lollcolAl1" .,., Krts ... 221l125O

RETAIL STORES OPEN MON 'SAT STORE 131 0 " B" E. Ed onger STORE 6 74 EI Camino Real #1 Sant a An a. CA 92 705 #2 Tu st on, CA 92680 Sh owr o om s. Ret a il . Ware ho use Sp eclall l on9 ,n Syste ms



......-.. cn-.

• SKIERS • JOGGERS • SKATERS • CYCLERS YoorrosthBM ttandfeel tt

1.75 229

1.80 ." 8 1." 9 1.48 .89 1.50 .79 .95 .95 3.95 1.75 .99 2.50 2.85 2,29 1.99 3 ..9 2.99 2,75 1.49 1.29 1." 9 3.25 3.25 4.85 1." 9 1.28 1.89 1.68 1.99 1.29 275 2.• 9 1.99 2.• 9 2."9 2.9 1 .9 1.95 .69 1.49 395 3,95 350 .59 1 "9 98 295 1.10 450 485 "40 1,25 1.50 59 "9 ." 9 "9 "9 89 89 a8 89


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5495 6295 00 35000 17900 16900 27900 25000

ATARI 800 Includ. .: Comput er Con sole , BASIC lang. Cart ridge, Educat ion System Ma sterCartridge, BASIC Language Progr amm ing Man ual, 8 00 Ope rator's Manual w/Notebook, Atan 410 Program Hecoeder, 8K RAM Modu le, Power Supply, 1V Switch Box. Dc Orllol •• •••••

WI1'H 9 VOICESI . 1f[W UWS llal SIlI. til h M lSl TIdn::io;1_ ~ ..," .tort_ .

2.75 2.75 .BO

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Personal Computer System ATARI800 $750.00 ATARI400 $449.00

1.75 1.95 1.95 1.85



_CW . . . . • •. . . . . . . 2195 III & R McdJln 2995

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1.10 1.29 1.85 1.10



16K Apple Upgrade Kit $62.95

PROCESSOR 6502 6502

Cromemco SD-SBC1 00 AIM 65 Cos mac Vip

P.O. Box 17329 Irvine, Cal if. 92713 Direct Order Lines: (7 14) 558·8813 . (800) 854·8230 or (800) 854·8241


ZOO ZOO 650 2 180 2

ACP PRICE 169.00 239.00 409. 00 239 .00 375 .00 199.00

ENCLOSURE Add 29.95 Add 39 .95 N/A N/A Add 49 .95 Inc.

FOR INT ERNATIONAL ORDERS ' 140 1 E. Bor c har d (7 14) 9 53 -0604 Sant aA na CA 9 27D5 TW X' 91 D-59 5.156 5





FLOPPY DISK I/O 177 1.01 8~ & Monlflowt..•.•. 20&85 4i.e5 uPlS372Nec:F1ooP'f 178 ' Duel FlooPf :ltt5 17t1-Q1 0Y1il floppy 3695 uPd765 F1oocJy •• • •.• •••••. • ~e,"

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n.. VISTA Y-ao Disk Dri _ S ptem . nHl n"'....... CIl*'ll' ...

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Ccnlrol ler (S-l 00J. Cue. Pow&r ~

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BASE II PRINTER eoColum" . GOl.!ntoI '"",",I_ PtrMinul. ~

call Fo r Volume Discounts


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25 00 I G,lI5


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RETAIL STO RES OPEN MON 'SAT STORE 13 10 " B" E. Ed lng e r STORE 6 74 EI Cam i n o Real #2 T ust in . C A 9 2680 #1 Sant a An a. CA 92 705 Sh owro o m s, Reta .I, W areh ou se Sp ec lall zln9 In System s


13 S1otMottle r ~ lWloICl 32. (l S 9 5aol ~ ('NMC) •• NlI5

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FOR INTERNAT IO NAL ORDERS : 1401 E. Bo. ch ard (71 4) 953 06 04 Sant a Ana CA 9 2 70 5 TWX' 9 1 ~ 595'1565





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Free Information Number 27


I F YOU " Avt ALREADT PVIilC"'UD T" [ 1 17""7 7 tll l P you "'AY IU" T.. t PC IO AAD ..... 0 I " STAUCl I OtlS l)Irj \. T . C2J WlS $1,. 00

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Advanced Computer Products

120- 121 14·15,42.75,77

All Electronics ............



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Cover 4 94

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101 8- 11

National Technical Schools 41





Non-Linear Systems

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Your future in electronics depends on knowing • mIcroprocessors

To advance in the el ec tronic-oriented world of today and tomorrow - you need to understand microprocessors. Now, Heath/Zenith Educational Systems brings everything together in one comple te, easy-to-follow self-instructional course on microprocessors - so you can gain the knowledge needed to secure your future in electronics. Heath/Zenith's Microprocessor Course - as does every program in the Heath/Zenith Electronics Education line reinforces each concept FOUR ways : 1. You HEAD cl ear', c o ncise t ext mat erial. 2 . You S E E large , c o lo rfu l visuals . 3 . You II EAH audio c assette tapes whi ch reinforc e mat e rial present ed in the text mat erial and vis u a ls . 4 . You PEH FOHi\I progr-ammlng and int erfacing expe r im e n ts , whi ch g ive you h ands-on e xpe r ie nc e in pr-ogramrnlng and Int erfacing mlcroproc essors.

In te r facing - w it h ROM , HAM, d iapl ays and switches, O/A and

AID converte rs; using t h e Peripheral Int e rfa c e Adapter (PIA). Nu mber Syste m" a nd Codes, Microcomputer Basic" and Co m p u ter Arithmetic.

Turn to page s 74 and 75 of the latest Heathkit Catalog for full details on the Microprocessor Course and Trainer - and our complete line of top-qu ality Heath/Zenith Courses. If you don't al ready have a Heathkit Catalog, send for your free copy at one of the addresses below. Or p ick up your copy a t the nearest Heathkit Elec tronic Center" in the U.S. and Canada, where Heath/Zenith Educational Courses are displayed and sold.

Sixty-two different electronic components are in cluded, to make the Heath/Zenith Course an even better' value. These parts are u sed in the hands-on programming and interfacing experiments. The Heath/Zenith Microprocessor Course is backed by a Microprocessor Trainer, used to perform the experiments . Bas ed on the popular 6800 micropr-ocessor, this Trainer functions as a miniature .d igital compu ter, Built-in lK ROM monitor program co n tro ls operation.Six-digit LED display provides address, data readout.

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In the experiments, you work with ac tual components to gain hands-on experience and confidence, and to make learning more effective.


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